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Masculinity matters (but mostly if you’re muscular):

A meta-analysis of the relationships between sexually dimorphic traits in
men and mating/reproductive success

Lidborg, L. H.¹*, Cross, C. P.², Boothroyd, L. G.¹

1. Department of Psychology, Durham University, South Road, Durham, DH1 3LE, UK

2. School of Psychology and Neuroscience, University of St Andrews, St Mary's St Mary's
Quad, South St, St Andrews KY16 9JP, UK

*Author for correspondence: linda.h.lidborg@durham.ac.uk

Word count: 6128

Keywords: sexual selection; human evolution; sexual dimorphism; masculinity; mating
success; reproductive success

Abstract

Humans are sexually dimorphic: on average men significantly differ from women in body

build and composition, craniofacial structure, and voice pitch, likely mediated in part by

developmental testosterone exposure. Hypotheses which attempt to explain the evolution of

dimorphism in humans, such as the immunocompetence handicap hypothesis and the male-

male competition hypothesis, assume that more dimorphic (i.e. masculine) men have

historically achieved greater mating success, resulting in greater reproductive success. This is

either because women select more masculine men due to their greater immune function,

because more masculine men expend more energy on mating effort, or because more

masculine men out-compete their rivals for other routes to mating success. Thus far, however,

evidence for an association between masculinity and reproductive success is unclear. We

conducted the most comprehensive meta-analysis to date, on the relationship between

masculinity in six domains (faces, bodies, voices, height, digit ratios, and testosterone levels)

and mating/reproductive success, comprising 434 effect sizes from 91 studies (total N =

155,348). Body masculinity, i.e. muscularity and strength, predicted both mating and
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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reproductive success. Voice pitch, height, digit ratios and testosterone levels all predicted

mating but not reproductive outcomes. Facial masculinity did not significantly predict either.

Our findings support arguments that muscularity/strength can be considered sexually selected

in humans, but raise concerns over other forms of masculinity, most especially facial

masculinity. We are also constrained by lack of reproductive data, particularly from naturally

fertile populations. Our data thus highlight the need to increase tests of evolutionary

hypotheses outside of industrialised populations.

Introduction

Sexual dimorphism refers to sex differences in morphological and behavioural traits,

excluding reproductive organs (Plavcan, 2001), with particular emphasis on traits thought to

have evolved through sexual selection (Crook, 1972). Humans are a sexually dimorphic

species (albeit moderately so compared to our closest primate relatives: Plavcan, 2001).

Sexual selection is commonly argued to have acted more strongly on male traits, as a

consequence of greater variance in males’ reproductive output (Hammer et al., 2008) and a

male-biased operational sex ratio, i.e. a surplus of reproductively available men relative to

fertile females.

Dimorphic traits that are exaggerated amongst males are typically referred to as

masculinity. In humans, masculine faces are characterised by features such as a pronounced

brow ridge, a longer lower face, and wide mandibles, cheekbones and chins (Swaddle &

Reierson, 2002). Men are, on average, 7-8% taller than women (Gray & Wolfe, 1980) and

weigh approximately 15% more (Smith & Jungers, 1997). Relative to this fairly modest body

size dimorphism, upper body musculature and strength are highly dimorphic in humans:

compared to women, men have 61% more overall muscle mass, 78% more muscle mass in the

upper arms, and 90% greater upper body strength (Lassek & Gaulin, 2009). Men’s bodies
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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tend to have a V- or wedge-shape; their shoulders are broader in relation to their hips

compared to women, showing a greater shoulder-to-hip ratio (Hughes & Gallup, 2003; Singh,

1993). A closely related measure, also contributing to the impression of a V-shaped torso, is

the waist-to-chest ratio (Tovée et al., 1999; Weeden & Sabini, 2007). Second-to-fourth finger

(digit) length ratios are sexually dimorphic, with men showing a lower 2D:4D than women

(Apicella et al., 2016; Manning, 2002), particularly in the right hand (Hönekopp et al., 2006).

Fundamental frequency, commonly referred to as voice pitch (Atkinson et al., 2012), is

produced by vibration of the vocal folds and is influenced by the vocal tract’s size and shape

(Evans et al., 2008). Under the influence of androgen production in puberty the vocal fold

length in boys increases, thus deepening the voice (Harries et al., 1998) and resulting in an

adult male voice pitch approximately six standard deviations lower than women’s (Puts et al.,

2014). The development of these dimorphic traits in men is influenced by prenatal and

pubertal exposure to androgens, particularly testosterone. With the exception of 2D:4D, which

is commonly claimed to be influenced primarily by prenatal testosterone levels and is present

at birth (Galis et al., 2010; Richards et al., 2019), masculine traits generally develop or

become exaggerated following a surge in T production at sexual maturity (Butterfield et al.,

2009; Fechner, 2003; Weston et al., 2007) – although it is not necessarily clear whether the

size of that surge corresponds directly to the extent of trait expression.

The evolution of sexual dimorphism in the human lineage is, to date, not well

understood (Plavcan, 2001). We are often forced to test hypotheses about human evolution in

modern, industrialised populations, but data from other sources are imperative. Fossil records

provide clues to the evolution of skeletal dimorphism; however, fossil evidence can also

potentially be misleading and is not informative in terms of soft tissue dimorphism (Plavcan,

2012). Comparative evidence from our primate relatives can provide further clues, as can data

from contemporary small-scale, naturally fertile societies. If a trait which is proposed to be

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sexually selected increases mating/reproductive success in such populations, that indicates

that the trait may also have increased mating/reproductive success ancestrally (Hill et al.,

2016).

Two main hypotheses have been proposed to explain how and why masculine traits

evolved in men. According to the immunocompetence handicap hypothesis (Folstad & Karter,

1992), male sexually dimorphic traits across species index heritable immunocompetence, i.e.

good genetic quality. This hypothesis rests upon the notion that testosterone has

immunosuppressive properties, increasing vulnerability to pathogens (Muehlenbein &

Bribiescas, 2005). Hence, amongst humans, only men whose immune systems are sufficiently

robust to cope with the negative impact of high testosterone levels should be able to develop

masculine traits, rendering such traits costly signals of genetic quality. Masculine men should

therefore produce better quality offspring, and thereby also be able to attract a greater number

of partners. This suggests that masculinity in men is intersexually selected and evolved or was

maintained through female choice.

The immunocompetence hypothesis has been widely applied to facial masculinity in

particular. However, this hypothesis is also increasingly criticised, with respect to inconsistent

findings regarding both the putative associations between testosterone/testosterone-dependent

traits and health outcomes as well as the extent to which such traits are actually attractive to

women - both of which are key predictions of the hypothesis. For example, recent evidence

suggests that testosterone may have a modulating rather than suppressive effect on immune

functioning (Nowak et al., 2018), and facial masculinity is not consistently linked to better

health (Boothroyd et al., 2013; Foo et al., 2020; Zaidi et al., 2019). Evidence is similarly

mixed regarding the claim that women are attracted to masculinity in men’s faces (Little,

2015; Scott et al., 2013).

bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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An alternative hypothesis, the male-male competition hypothesis, is that formidable (i.e.

physically strong and imposing) men are better equipped to compete with other men for

resources, status, and partners, either through direct physical contests or by deterring rivals

(Hill et al., 2016; Sell et al., 2012). Greater stature and increased physical strength, especially

in the upper body, is arguably advantageous in direct contests, and strength cues such as

increased musculature are likely to intimidate competitors. Indeed, people treat physical

strength as a proxy of fighting prowess (Sell et al., 2009) and, in assessing overall strength,

favour cues found in the upper body (Durkee et al., 2018). Other traits, such as facial

masculinity and voice pitch, do not directly impact fighting prowess, but may have an indirect

relationship with formidability (Butovskaya et al., 2018; Haselhuhn et al., 2015; Jordan et al.,

2018; Little et al., 2015; Puts & Aung, 2019; Scott et al., 2014). Furthermore, perceived

dominance appears to mediate the relationship between formidability and mating success (Hill

et al., 2013; Kordsmeyer et al., 2018). Thus, being formidable may increase masculine men’s

reproductive success by enabling them to accrue a greater number of partners through the

benefits of dominance (e.g. social capital and/or resources). This proposal has garnered

increasing support in recent years (Hill et al., 2016; Puts, 2016). While this hypothesis

suggests that masculinity in men is intrasexually selected, this type of selection may also work

in conjunction with female choice if women preferentially mate with formidable/dominant

men (Kordsmeyer et al., 2018; Slatcher et al., 2011).

Reproductive success can be achieved either by producing better quality offspring

and/or a greater quantity of offspring; the latter may (in men) be mediated by mating with a

greater number of partners. Previous studies testing the relationships between masculine traits

and fitness outcomes have produced a mixture of positive, negative and null results,

highlighting the need for meta-analytic evidence. To date, however, such analyses are rare,

and typically exclude many aspects of masculinity in addition to focussing exclusively on

bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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mating or reproductive outcomes. Van Dongen and Sprengers (2012) meta-analysed the

relationships between men’s handgrip strength (HGS) and sexual behaviour in only three

industrialised populations (showing a weak, positive association [r = .24]). Across 33 non-

industrial societies, von Rueden and Jaeggi (2016) found that male status (which included, but

was not limited to, measures of height and strength) weakly predicted reproductive success

(overall r = .19); in contrast, Xu, Norton and Rahman (2018) reported no significant

association between men’s height and offspring numbers across 16 studies. Lastly, a meta-

analysis of 16 effects by Grebe, Sarafin, Strenth and Zilioli (2019) showed that men with high

testosterone levels invested more in mating effort, indexed by mating with more partners and

showing greater interest in casual sex (r = .22). Facial masculinity, voice pitch, and 2D:4D

have never been meta-analysed in relation to mating/reproduction.

The present article is the first to meta-analyse the relationships between five sexually

dimorphic traits in humans (facial masculinity, body masculinity, 2D:4D, voice pitch, and

height) and both mating and reproductive success. According to the immunocompetence

handicap hypothesis, the association between masculine traits and mating/reproductive

outcomes rests upon the notion that masculine traits index testosterone levels. We therefore

also included testosterone levels as a predictor. We focussed on fertility outcomes (offspring

numbers and age of reproductive onset) as indices of reproductive success, and mating

success/mating strategies as a proxy thereof. Both the immunocompetence hypothesis and the

male-male competition hypothesis predict that masculine men should enjoy greater

reproductive and mating success, although the mechanism by how this is achieved differs.

While our aim was not to evaluate the two hypotheses against each other, we note that the

male-male competition hypothesis predicts that it is primarily physically formidable traits,

such as body masculinity and height, that should be associated with increased
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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reproductive/mating success. The immunocompetence hypothesis, on the other hand, has

primarily been applied to facial masculinity.

Methods

Literature search and study selection

A systematic search was carried out between November 2017 and February 2018 using the

databases PsycINFO, PubMed, and Web of Science. Studies were also retrieved through

cross-referencing, citation searches, citation alerts, and by asking researchers directly for data

on social media and through personal communications. Studies submitted for analysis up to 1

September 2019 were accepted. Eligible studies included at least one of the following

predictors: facial masculinity, body masculinity (strength, body shape, or muscle mass/non-fat

body mass), 2D:4D, voice pitch, height, or testosterone levels. Outcome measures included

reproductive and mating outcomes; in traditional populations without access to modern

medicine and contraception, reproductive success can be measured directly. In industrialised

populations, on the other hand, mating-based proxies of reproductive success must be used

instead, such as number of spouses and number of sexual partners, as these should have

correlated with reproductive success in men under ancestral conditions (Pérusse, 1993). Thus,

the outcome measures were:

- Reproductive success, i.e. fertility: number of offspring and grand-offspring, and

reproductive onset (early reproduction increases potential reproductive output in traditional

populations, since that allows for a greater lifetime number of offspring; this variable was thus

reverse coded).

- Mating success: global sociosexuality (Penke & Asendorpf, 2008; Simpson & Gangestad,

1991) and specific measures of mating attitudes and mating behaviours where:

i. Mating attitudes included: preferences for short-term mating/short-term mating

bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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orientation, and sociosexual attitudes and desires.

ii. Mating behaviours included: number of sexual partners (NSPs; during one’s lifetime

or within a specified time period), number of one-night-stands/short-term relationships,

number of potential conceptions (Pérusse, 1993), sociosexual orientation behaviour subscale,

extra-pair copulations/partners, age at first sexual intercourse/encounter (early sexual activity

is associated with increased mating success since it allows for a greater lifetime number of

sexual partners; this variable was therefore reverse coded), and number of spouses.

Both published and unpublished studies were eligible, but we restricted our sample to

studies where participants were at least 17 years old. If key variables were collected but the

relevant analyses were not conducted or not reported, authors were asked to provide effect

sizes or raw data. If data were reported in more than one study, we selected the analysis with

the larger sample size or greater inclusion of appropriate control variables. Studies using

measures that were ambiguous and/or not comparable to measures used in other studies were

excluded. Twin studies where participants were sampled as pairs, population level studies,

and studies analysing both sexes together were also discarded, as well as articles that were not

written in English. Multiple measures from the same study were retained if they met the other

criteria. We chose Pearson’s r as our effect size measure and effect sizes not given as r were

converted; where the relevant relationships had been analysed but effect sizes were not

convertible and/or not possible to obtain from the authors, the study was excluded. Where

non-significant results were not stated in the paper and could not be obtained, an effect size of

0 was assigned (excluding those effect sizes from the analyses made no difference to the

results, so will not be discussed further). In total, 91 studies were selected, comprising 434

effect sizes from 92 samples and 155,348 unique participants. This exceeds the number of

studies for each of the meta-analyses published previously (Grebe et al., 2019; Van Dongen &

Sprengers, 2012; Von Rueden & Jaeggi, 2016; Xu et al., 2018). Please see SI for full details
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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about the literature search, study/measure selection decisions, effect size conversions, and the

study list.

Results

Statistical analyses

We used the metafor package (Viechtbauer, 2010) in R 3.6.2 (R core team, 2019). metafor

transforms Pearson’s r to Fisher’s z for analysis; effect sizes were converted back to r for

presentation of results. Analyses were conducted using random-effects models. Twelve main

analyses were carried out assessing the relationships between each masculine trait and

mating/reproductive success, respectively. For mating success, we also conducted separate

subgroup analyses for mating attitudes and mating behaviours. Subgroup analyses were also

conducted for low versus high fertility samples (with a cut-off of three or more

children/woman on average within that population at the time of sampling). To test for the

impact of study characteristics, we also performed a series of moderation analyses on factors

linked to study quality (e.g. controls for age where relevant, objective vs subjective measures,

repeat measurements) or generalisability (e.g. sexual orientation of participants). Full lists of

moderators are given in SI; significant moderators are reported below. In all analyses, effect

sizes were clustered by sample and by study. Only relationships with a minimum of three

independent samples from a minimum of two separate studies were analysed. For 2D:4D and

voice pitch, effects were reverse coded prior to analysis because low values denote greater

masculinity and these traits should therefore be negatively associated with fitness outcomes.

Thus, for all traits, the predicted relationships with mating/reproductive success were positive.

Additional details and full results, including R code, can be found in SI.
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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Mating success

Main analyses. The first set of analyses tested the prediction that masculine traits and

testosterone levels are associated with increased mating success. As can be seen in Tables 1

and 2, for all traits bar facial masculinity, greater masculinity/testosterone levels predicted

significantly higher mating success. The strongest associations with mating outcomes were

seen in terms of body masculinity (r = .133, 95% CI: [0.091, 0.176]), voice pitch (r = .132,

95% CI: [0.061, 0.204]), and testosterone levels (r = .097, 95% CI: [0.070, 0.125]);

moderation analyses showed that these three effects did not significantly differ from each

other (p > .05). Height and 2D:4D were also significant predictors of mating success, but

showed significantly smaller effect sizes than body, voice or testosterone levels (height: r =

.057, CI: [0.027, 0.087]; 2D:4D: r = .034, CI: [0.000, 0.069]). The relationship between facial

masculinity and mating success was not significant (r = 0.080, 95% CI: [-0.003, 0.164]).

Table 1
Facial masculinity, body masculinity and 2D:4D predicting mating success: main analyses and
subgroup analyses of mating success type and sample type
Mating success (MS)

Facial masculinity Body masculinity 2D:4D

Outcome
Sample
MS (all) r = .080 (-0.003-0.164) r = .133 (0.091-0.176) r = .034 (0.000-0.069)
Full sample k = 30, s = 11, n = 948 k = 121, s = 32, n = 7939 k = 84, s = 22, n = 66807
Q(df = 29) = 54.834, Q(df = 120) = 297.472, Q(df = 83) = 101.994,
p = .003 p < .001 p = .077
MS att. r = .095 (-0.072-0.263) r = .078 (0.002-0.155) r = .035 (-0.061-0.132)
Full sample k = 5, s = 4, n = 407 k = 20, s = 9, n = 922 k = 19, s = 7, n = 504
Q(df = 4) = 8.684, Q(df = 19) = 17.606, Q(df = 18) = 24.141 ,
p = .070 p = .549 p = .151
MS beh. r = .025 (-0.059-0.109) r = .142 (0.099-0.187) r = .038 (0.002-0.078)
Full sample k = 22, s = 8, n = 755 k = 91, s = 31, n = 7738 k = 51, s = 19, n = 1607
Q(df = 21) = 37.044, Q(df = 90) = 267.876, Q(df = 50) = 64.049,
p = .017 p < .001 p = .087
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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MS (all) r = .089 (-0.001-0.179) r = .135 (0.091-0.180) r = 0.038 (-0.002-0.073)

Low fert. k = 28, s = 10, n = 913 k = 117, s = 28, n = 7572 k = 82, s = 21, n = 66751
samples Q(df = 27) = 54.287, Q(df = 116) = 289.080, Q(df = 81) = 101.369,
p = .001 p < .001 p = .063
MS (all) s=1 r = .105 (-0.069-0.280) s=1
High fert. k = 4, s = 4, n = 367
samples Q(df = 3) = 7.282,
p = .063
Note. MS att. = Mating success attitudes; MS beh. = Mating success behaviours; fert. = fertility; k =
number of observations; s = number of samples; n = number of unique participants. Statistically
significant associations are bolded.

Table 2
Voice pitch, height and testosterone levels predicting mating success: main analyses and subgroup
analyses of mating success type and sample type
Mating success (MS)

Voice pitch Height T levels

Outcome
Sample
MS (all) r = .132 (0.061-0.204) r = .057 (0.027-0.087) r = .097 (0.070-0.125)
Full sample k = 8, s = 5, n = 443 k = 62, s = 25, n = 43686 k = 62, s = 20, n = 7022
Q(df = 7) = 2.334, Q(df = 61) = 263.247, Q(df = 61) = 63.732,
p = .939 p < .001 p = .381
MS att. s=0 r = .028 (-0.013-0.068) r = .110 (0.032-0.188)
Full sample k = 9, s = 6, n = 4232 k = 19, s = 10, n = 978
Q(df = 8) = 5.137, Q(df = 18) = 24.197,
p = .743 p = .149
MS beh. r = .124 (0.043-0.206) r = .054 (0.021-0.087) r = .085 (0.059-0.112)
Full sample k = 7, s = 5, n = 443 k = 48, s = 24, n = 42179 k = 31, s = 16, n = 6704
Q(df = 6) = 2.162, Q(df = 47) = 247.032, Q(df = 30) = 27.928,
p = .904 p < .001 p = .574

MS (all) r = .129 (0.055-0.204) r = .055 (0.024-0.086) r = .103 (0.074-0.133)

Low fert. k = 7, s = 4, n = 388 k = 58, s = 21, n = 43310 k = 54, s = 19, n = 6734
samples Q(df = 6) = 2.234, Q(df = 57) = 259.576, Q(df = 53) = 58.777,
p = .897 p < .001 p = .272
MS (all) s=1 r = .089 (-0.016-0.193) s=1
High fert. k = 4, s = 4, n = 376
samples Q(df = 3) = 3.388,
p = .336
Note. MS att. = Mating success attitudes; MS beh. = Mating success behaviours; fert. = fertility; T =
testosterone; k = number of observations; s = number of samples; n = number of unique
participants. Statistically significant associations are bolded.
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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Subgroup and moderator analyses. For all predictors, the majority of effect sizes (94 %) came
from low fertility samples.

The nonsignificant relationship between facial masculinity and mating success was not

moderated by measurement type. Effect sizes were larger for mating attitudes than for mating

behaviours, but the difference was not statistically significant. All samples bar one were from

low fertility populations.

Body masculinity predicted both mating behaviours and mating attitudes in the full

sample, and moderator analysis showed no difference in the strength of these two

relationships. While the positive relationship between body masculinity and mating success

was significant in the 28 low fertility samples and nonsignificant in the 4 high fertility

samples, moderator analysis did not show the strength of relationship to differ between these

two population types. Furthermore, moderation analyses of type of body masculinity showed

that muscularity and strength did not predict mating success differently, but that body shape

was a significantly weaker predictor of mating success than strength (B = -0.089, p = .003).

For muscularity and body shape, which can be assessed either through subjective ratings or

objective measurements, effect sizes were larger for subjectively rated masculinity (B =

0.178, p = .007). For objectively measured masculinity, there was a significant effect of

number of measurements, with a stronger effect for studies with three measurements

compared to studies with an unspecified number of measurements (B = 0.128, p = .045).

Additionally, effect sizes were larger in studies that had controlled (vs not controlled) for

participant age (B = 0.096, p = .031), smaller in non-student than student populations (B = -

0.118, p = .020), smaller in non-published than published results (B = -0.086, p = .029), and

smaller in samples that were not exclusively heterosexual (B = -0.085, p = .035).

For 2D:4D, effect sizes did not differ between mating attitudes and mating behaviours.

All samples except one were from low fertility populations. Effect sizes were larger in studies
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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where 2D:4D had been measured through hand scans instead of directly from hands (B =

0.091, p = .032), when 2D:4D had been measured three times compared to an unspecified

number of times (B = 0.102, p = .006), and in studies where non-normally distributed

variables had been transformed to normality (B = 0.094, p = .010). Ethnicity was also a

significant moderator, with weaker effects in samples that were not predominantly white (B =

-0.080, p = .014). There was no difference between left and right 2D:4D.

No moderation analyses could be carried out for voice pitch due to an insufficient

number of studies.

Height had a significant effect on mating behaviours but not mating attitudes, but the

difference between them was not significant. The association between height and mating

success was significant in low fertility samples and not in high fertility samples, but there was

no significant difference between these two associations. There were no other significant

moderators of relationships between height and mating success.

Testosterone levels significantly predicted mating attitudes and mating behaviours to a

similar degree. Only one sample was from a high fertility population. Effect sizes were

significantly weaker in non-exclusively heterosexual samples (B = -0.057, p = .004), and

larger in studies where variables had been transformed to normality (B = 0.055, p = .019).

Inclusion bias/heterogeneity. Since the analysis included unpublished data, the funnel plots in

this case indicate availability bias rather than publication bias. With the exception of voice

pitch, for which we did not have many effects, visual inspection of funnel plots indicated that

they were generally symmetric. There was significant heterogeneity of effect sizes for facial

masculinity, body masculinity, and height.

bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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Figure 1. Funnel plots of effect sizes for mating success (MS).

Reproductive success

In the second set of analyses, we tested the hypothesis that masculine traits and testosterone

levels positively predict reproductive success. As Tables 3 and 4 show, relationships were in

the predicted direction, but body masculinity was the only significant predictor (r = .119, 95%

CI: [0.058, 0.182]). The only trait with an effect size significantly different from body

masculinity was height (B = -0.093, p = .017); the other traits did not significantly differ.
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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Table 3
Facial masculinity, body masculinity and 2D:4D predicting reproductive success: main analyses
and subgroup analyses of sample type
Reproductive success (RS)

Facial masculinity Body masculinity 2D:4D

Outcome
Sample
RS r = .072 (-0.097-0.242) r = .119 (0.058-0.182) r = .053 (-0.029-0.136)
Full sample k = 4, s = 4, n = 1232 k = 12, s = 8, n = 897 k = 16, s = 7, n = 84223
Q(df = 3) = 8.776, Q(df = 11) = 6.036, Q(df = 15) = 20.889,
p = .032 p = .871 p = .140
RS s=1 s=1 r = .052 (-0.065-0.169)
Low fert. k = 7, s = 3, n = 83845
samples Q(df = 6) = 8.335,
p = .215
RS r = .030 (-0.278-0.338) r = .146 (0.083-0.212) r = .056 (-0.088-0.199)
High fert. k = 3, s = 3, n = 895 k = 11, s = 7, n = 626 k = 9, s = 4, n = 378
samples Q(df = 2) = 8.692, Q(df = 10) = 3.026, Q(df = 8) = 10.118,
p = .013 p = .981 p = .257
Note. Fert. = fertility; k = number of observations; s = number of samples; n = number of unique
participants. Statistically significant associations are bolded.

Table 4
Voice pitch, height and testosterone levels predicting reproductive success: main analyses and
subgroup analyses of sample type
Reproductive success (RS)

Voice pitch Height T levels

Outcome
Sample
RS r = .093 (-0.064-0.251) r = .011 (-0.038-0.060) r = .039 (-0.067-0.145)
Full sample k = 4, s = 3, n = 143 k = 28, s = 25, n = 22326 k = 3, s = 3, n = 351
Q(df = 3) = 3.190, Q(df = 27) = 401.101, Q(df = 2) = 0.387,
p = .363 p < .001 p = .824
RS s=0 r = -.028 (-0.097-0.041) s=2
Low fert. k = 9, s = 9, n = 17741
samples Q(df = 8) = 256.064,
p < .001
RS r = .093 (-0.064-0.251) r = .055 (-0.005-0.115) s=1
High fert. k = 4, s = 3, n = 143 k = 19, s = 16, n = 4585
samples Q(df = 3) = 3.190, Q(df = 18) = 26.606,
p = .363 p = .087
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
(which was not certified by peer review) is the author/funder. It is made available under a CC-BY-NC-ND 4.0 International license.

Note. Fert. = fertility; T = testosterone, k = number of observations; s = number of samples; n =

number of unique participants. Statistically significant associations are bolded.

Figure 2. Forest plot of the association between body masculinity and reproductive success. Effect
sizes are shown as Z-transformed r, with 95% confidence intervals in brackets. The width of the
diamond corresponds to the confidence interval for the overall effect.

Subgroup and moderator analyses. The majority (70 %) of observations were from high

fertility samples (see Tables 3 and 4). Subgroup analyses/moderation analyses of low versus

high fertility samples could only be conducted for 2D:4D and height; effect sizes did not

differ significantly between high and low fertility samples. Due to too few observations, no

moderation analyses could be performed for facial masculinity, voice pitch, or testosterone

levels. There were no significant moderators of the relationship between body masculinity and

reproductive success. Effect sizes were significantly smaller for 2D:4D studies that had not

controlled for finger injuries (B = -0.128, p = .003) than ones that had. For height, the

relationship with RS was significantly stronger in non-exclusively heterosexual samples (B =

0.115, p = .019).
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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Inclusion bias/heterogeneity. Visual inspection of funnel plots suggested that while the effects

for voice pitch, height and testosterone were symmetrically distributed, our analysis may have

lacked studies for the other three traits. Facial dimorphism and height showed significant

heterogeneity.

Figure 3. Funnel plots of effect sizes for reproductive success (RS).

Overall findings

Combining all types of masculinity, the overall association with mating success was r = .092

(95% CI: [0.072, 0.112]) and with reproductive success r = .037 (95% CI: [-0.003, 0.076]);

the difference between these two effects was not significant. Moderation analyses of outcome

type (mating versus reproductive success) for each trait showed that facial masculinity, voice
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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pitch, height, and testosterone levels had weaker associations with reproductive than mating

success, but the differences were not significant. However, we had far fewer observations for

reproductive success, so this might reflect lack of power. For body masculinity and 2D:4D,

there was no difference between outcome types.

Discussion

In this first comprehensive meta-analysis of the relationships between masculine

traits/testosterone levels and mating/reproductive success in men, mating success – which was

predominantly measured in low fertility samples – was positively associated with all of the

masculine traits we assessed, apart from facial masculinity. In contrast, reproductive success

was measured mainly in high fertility samples and was correlated only with body masculinity.

The strongest correlations with mating success were r = .13 (for both body masculinity and

voice pitch), and body masculinity predicted reproductive success with r = .12. These three

effects are potentially meaningful in an evolutionary context. As benchmarks for interpreting

correlations, Funder and Ozer (2019) suggest that a correlation of .10, while being a small

effect that is unlikely to be meaningful in terms of single events, has the potential to be

influential over a long time period, and a medium-size correlation of .20 can be consequential

both in the short- and long-term. The cumulative effect of relatively ‘weak’ correlations can

therefore be of real consequence, particularly when considered in the long run and in large

populations.

Compared to previous meta-analyses, assessing associations between handgrip strength

and mating outcomes (Van Dongen & Sprengers, 2012), height/strength and reproductive

outcomes (von Rueden & Jaeggi, 2016; Xu et al., 2018), and testosterone levels and mating

effort (Grebe et al., 2019), our analysis benefits from more comprehensive measures of

dimorphism, larger sample sizes, and inclusion of more unpublished effects. With the
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
(which was not certified by peer review) is the author/funder. It is made available under a CC-BY-NC-ND 4.0 International license.

exception of Xu et al. (2018), we observe smaller effect sizes, suggesting that other meta-

analyses overestimated the association between masculinity and fitness outcomes.

As the only trait in our analysis that is consistently (and most strongly) correlated with

fitness outcomes across populations, body masculinity is the only trait we can conclude

appears to be under present selection in naturally fertile populations. Regardless of how other

traits may influence or be linked to men’s mating strategies in low fertility populations, these

strategies show no evidence of translating into higher fertility, either because these traits

operate differently in high fertility populations, or because these mating strategies are

insufficient to achieve higher reproductive success without body masculinity. Since traits such

as strength and muscularity are associated with formidability, this finding lends support to the

male-male competition hypothesis. In species with male-male competition, males tend to

evolve to become larger, stronger and more formidable than females, as they are in humans.

There is reason to suspect that male-male violence has influenced human evolution (Gat,

2015; Hill et al., 2016): male intergroup aggression increases mating/reproductive success in

both non-industrialised human societies and non-human primates (Glowacki & Wrangham,

2015; Manson et al., 1991). The relationship between formidable traits and fitness outcomes

might, however, be mediated by other factors that are important in mate choice. For example,

features that are advantageous in intraspecies conflicts may also be advantageous when

hunting game (Sell et al., 2012); Smith et al. (2017) reported that in a hunter-gatherer

population, men with greater upper body strength and a low voice pitch had increased

reproductive success, but this relationship was explained by hunting reputation.

It is of course possible that different selection pressures may have contributed to the

evolution of different sexually dimorphic traits. Male-male competition for resources and

mates, female choice, and intergroup violence are all plausible, non-mutually exclusive

explanations (Plavcan, 2012). Traditionally in human sexual selection research, however, the
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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immunocompetence handicap hypothesis has attracted the most attention as an explanation of

how masculine traits evolved in men. Most research based on this hypothesis has focussed

particularly on masculinity in men’s facial structure as an indicator of heritable

immunocompetence (i.e. good genes), which should then be associated with heritable

mating/reproductive success. While we find that the effect of facial dimorphism on mating

success is similar in strength to that of other traits (r = .08), this association is not significant.

Furthermore, the effect of facial masculinity on global mating success is largely driven by

mating attitudes and is close to zero for mating behaviours, suggesting that men’s facial

masculinity exerts virtually no influence on female choice. Additionally, the influence of

facial masculinity on reproductive success in high fertility samples is extremely weak (r =

.03). These findings contradict a large body of literature claiming that women’s preferences

for masculinity in men’s faces are adaptive, and rather indicate that such preferences (to the

extent that they exist at all) are a modern anomaly only found in industrialised populations, as

suggested by Scott et al. (2014).

While 2D:4D, voice pitch, height, and testosterone levels significantly predict mating

success in our analysis, none of these traits are significantly associated with reproductive

outcomes. The latter was primarily measured in high fertility populations, where offspring

numbers are not constrained by widespread use of contraception. It is thus mainly in these

naturally fertile contexts present selection may take place. Our findings mean that for none of

these traits do we have evidence suggesting that greater mating success translates into greater

reproductive success; we therefore have no evidence that these traits are currently under

selection, but we also note that we are constrained by a lack of data from these populations.

A limitation of our analysis is that we only assessed linear relationships, ignoring

possible curvilinear associations. There is evidence suggesting that moderate levels of

masculinity might be associated with increased reproductive success (see e.g. Boothroyd et
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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al., 2017 for offspring survival rates) and perceived attractiveness (Frederick & Haselton,

2007; Johnston et al., 2001; Sell et al., 2017), with a decrease for very high levels of

masculinity. However, given that such results typically indicate that greater-than-average

levels of masculinity are associated with peak fitness/attractiveness, we would still expect to

see positive, albeit weak, linear relationships.

Another caveat is that testosterone is reactive and decreases for example when men

enter a relationship or get married (Archer, 2006; Holmboe et al., 2017), when they become

fathers (Archer, 2006; Lee et al., 2011) or engage in childcare (Archer, 2006); thus, men

whose circulating testosterone was previously high may show declining testosterone levels

because their fatherhood status has changed, meaning we cannot determine with certainty

whether there really is no relationship between testosterone levels and reproductive outcomes.

In our analysis, men with high testosterone levels also have higher mating success, but since T

also motivates sexual behaviour (Roney & Gettler, 2015), this raises the possibility that high

T men pursue more mating opportunities which increases their mating success, or conversely

that high T results from many mating encounters.

Our findings raise important concerns for the human sexual selection field, particularly

with respect to whether mating success measures can be used as reliable indicators of likely

ancestral fitness. Since reproductive outcomes – for good reason – are not considered

meaningful fitness measures outside of naturally fertile populations, we typically test fitness

outcomes in industrialised populations using mating measures such as number of sex partners

and one-night-stands, under the assumption that such measures index mating strategies that

ancestrally would have increased men’s reproductive success. However, if mating outcomes

measured in low fertility populations truly indexed reproductive success in naturally fertile

contexts, we would expect traits that predict mating success to also predict reproductive

success across samples; we do not have evidence that this is the case. Our findings therefore
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
(which was not certified by peer review) is the author/funder. It is made available under a CC-BY-NC-ND 4.0 International license.

raise the question of whether these widely used measurements are truly valid proxies of what

we purport to be measuring. Our findings illustrate that when we attempt to test the same

underlying research questions using different measurements in different populations, this may

yield conclusions that are erroneous or misleading when applied outside of the studied

population. Wherever possible, we thus need to use the same measurements across

populations, or resist the temptation of applying our findings universally.

In summary, we used a large-scale meta-analysis of several masculine traits and both

mating and reproductive outcomes to test partially overlapping predictions of two hypotheses

explaining how and why such traits may have evolved in human males: i. that masculinity –

particularly in men’s faces - signals heritable immunocompetence and is thus favoured by

female choice, and ii. that masculinity – with emphasis on formidable traits in the body, such

as strength and muscle mass – increases men’s intrasexual competitiveness for mates. We

found that masculinity in all traits except facial morphology is associated with significantly

greater mating success. However, this increased mating success does not appear to translate

into greater reproductive success for any other trait than masculinity in men’s bodies. While

our aim in this analysis was not to evaluate the two hypotheses against each other, our

findings thus contradict the immunocompetence hypothesis and lend stronger support to the

male-male competition hypothesis. We also note that we are constrained by a lack of data

from natural fertility samples. We argue that our findings illustrate that when we test

hypotheses about human evolution largely in industrialised populations, we risk drawing

conclusions that are not supported outside of evolutionary novel, highly niche mating

contexts, and we call for greater sample diversity and more homogenous measurements in

future research.
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
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References

Alvergne, A., Faurie, C., & Raymond, M. (2009). Variation in testosterone levels and male
reproductive effort: Insight from a polygynous human population. Hormones and
Behavior, 56(5), 491-497. https://10.1016/j.yhbeh.2009.07.013
Apicella, C. L. (2014). Upper-body strength predicts hunting reputation and reproductive success in
Hadza hunter–gatherers. Evolution and Human Behavior, 35(6), 508-518.
https://doi.org/10.1016/j.evolhumbehav.2014.07.001
Apicella, C. L., Feinberg, D. R., & Marlowe, F. W. (2007). Voice pitch predicts reproductive success
in male hunter-gatherers. Biology letters, 3(6), 682-684.
https://dx.doi.org/10.1098%2Frsbl.2007.0410
Apicella, C. L., Tobolsky, V. A., Marlowe, F. W., & Miller, K. W. (2016). Hadza hunter-gatherer men
do not have more masculine digit ratios (2D:4D). American Journal of Physical Anthropology,
159(2), 223-232. https://doi.org/10.1002/ajpa.22864
Archer, J. (2006). Testosterone and human aggression: An evaluation of the challenge hypothesis.
Neuroscience and Biobehavioral Reviews, 30(3), 319-345.
https://doi.org/10.1016/j.neubiorev.2004.12.007
Arnocky, S., Carré, J. M., Bird, B. M., Moreau, B. J., Vaillancourt, T., Ortiz, T., & Marley, N. (2018).
The facial width-to-height ratio predicts sex drive, sociosexuality, and intended
infidelity. Archives of Sexual Behavior, 47(5), 1375-1385. https://10.1007/s10508-017-1070-x
Aronoff, J. (2017). Life history strategies, testosterone, and the anthropology of human
development (Doctoral dissertation, University of Alabama Libraries).
Atkinson, J. A. (2012). Anthropometric Correlates of Reproductive Success, Facial Configuration,
Risk Taking and Sexual Behaviors Among Indigenous and Western Populations: The Role of
Hand-grip Strength and Wrist Width (Doctoral dissertation, University at Albany. Department
of Psychology).
Atkinson, J., Pipitone, R. N., Sorokowska, A., Sorokowski, P., Mberira, M., Bartels, A., & Gallup, G.
G. (2012, Aug). Voice and Handgrip Strength Predict Reproductive Success in a Group of
Indigenous African Females. Plos One, 7(8), Article e41811.
https://doi.org/10.1371/journal.pone.0041811
Bogaert, A. F., & Fisher, W. A. (1995). Predictors of university men's number of sexual
partners. Journal of Sex Research, 32(2), 119-130.
https://psycnet.apa.org/doi/10.1080/00224499509551782
Booth, A., Johnson, D. R., & Granger, D. A. (1999). Testosterone and men's health. Journal of
Behavioral Medicine, 22(1), 1-19. https://doi.org/10.1023/a:1018705001117
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
(which was not certified by peer review) is the author/funder. It is made available under a CC-BY-NC-ND 4.0 International license.

Boothroyd, L. G., Cross, C. P., Gray, A. W., Coombes, C., & Gregson-Curtis, K. (2011). Perceiving
the facial correlates of sociosexuality: Further evidence. Personality and Individual
Differences, 50(3), 422-425. https://psycnet.apa.org/doi/10.1016/j.paid.2010.10.017
Boothroyd, L. G., Gray, A. W., Headland, T. N., Uehara, R. T., Waynforth, D., Burt, D. M., & Pound,
N. (2017). Male facial appearance and offspring mortality in two traditional societies. PloS
one, 12(1). https://doi.org/10.1371/journal.pone.0169181
Boothroyd, L. G., Jones, B. C., Burt, D. M., DeBruine, L. M., & Perrett, D. I. (2008). Facial correlates
of sociosexuality. Evolution and Human Behavior, 29(3), 211-218.
https://psycnet.apa.org/doi/10.1016/j.evolhumbehav.2007.12.009
Boothroyd, L. G., Scott, I., Gray, A. W., Coombes, C. I., & Pound, N. (2013). Male facial masculinity
as a cue to health outcomes. Evolutionary Psychology, 11(5).
https://doi.org/10.1177/147470491301100508
Butovskaya, M. L., Windhager, S., Karelin, D., Mezentseva, A., Schaefer, K., & Fink, B. (2018).
Associations of physical strength with facial shape in an African pastoralist society, the
Maasai of Northern Tanzania. PLoS ONE, 13(5), e0197738.
https://doi.org/10.1371/journal.pone.0197738
Butterfield, S. A., Lehnhard, R. A., Loovis, E. M., Coladarci, T., & Saucier, D. (2009). Grip strength
performances by 5- to 19-year-olds. Perceptual and Motor Skills, 109(2), 362-370.
https://doi.org/10.2466/pms.109.2.362-370
Charles, N. E., & Alexander, G. M. (2011). The association between 2D: 4D ratios and sociosexuality:
A failure to replicate. Archives of Sexual Behavior, 40(3), 587-595. https://10.1007/s10508-
010-9715-z
Chaudhary, N., Salali, G. D., Thompson, J., Dyble, M., Page, A., Smith, D., ... & Migliano, A. B.
(2015). Polygyny without wealth: popularity in gift games predicts polygyny in BaYaka
Pygmies. Royal Society Open Science, 2(5), 150054. https://doi.org/10.1098/rsos.150054
Crook, J. H. (1972). Sexual selection, dimorphism, and social organization in the primates. In Sexual
selection and the descent of man.
Durkee, P. K., Goetz, A. T., & Lukaszewski, A. W. (2018). Formidability assessment mechanisms:
Examining their speed and automaticity. Evolution and Human Behavior, 39(2), 170-178.
https://doi.org/10.1016/j.evolhumbehav.2017.12.006
Edelstein, R. S., Chopik, W. J., & Kean, E. L. (2011). Sociosexuality moderates the association
between testosterone and relationship status in men and women. Hormones and
Behavior, 60(3), 248-255. https://10.1016/j.yhbeh.2011.05.007
Evans, S., Neave, N., Wakelin, D., & Hamilton, C. (2008). The relationship between testosterone and
vocal frequencies in human males. Physiology & Behavior, 93(4), 783-788.
https://doi.org/10.1016/j.physbeh.2007.11.033
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
(which was not certified by peer review) is the author/funder. It is made available under a CC-BY-NC-ND 4.0 International license.

Falcon, R. G. (2016). Stay, stray or something in-between? A comment on Wlodarski et al. Biology
Letters, 12(5), 20151069. https://doi.org/10.1098/rsbl.2015.1069
Farrelly, D., Owens, R., Elliott, H. R., Walden, H. R., & Wetherell, M. A. (2015). The effects of being
in a “new relationship” on levels of testosterone in men. Evolutionary Psychology, 13(1),
147470491501300116.

Fechner, P. Y. (2003). The biology of puberty: new developments in sex differences. Cambridge
University Press. https://doi.org/10.1017/CBO9780511489716.003
Folstad, I., & Karter, A. J. (1992). Parasites, bright males, and the immunocompetence handicap. The
American Naturalist, 139(3), 603-622. https://doi.org/10.1086/285346
Foo, Y. Z., Simmons, L. W., Perrett, D. I., Holt, P. G., Eastwood, P. R., & Rhodes, G. (2020). Immune
function during early adolescence positively predicts adult facial sexual dimorphism in both
men and women. Evolution and Human Behavior.
https://doi.org/10.1016/j.evolhumbehav.2020.02.002
Frederick, M. J. (2010). Effects of early developmental stress on adult physiology and behavior. State
University of New York at Albany.
Frederick, D. A., & Haselton, M. G. (2007). Why is muscularity sexy? Tests of the fitness indicator
hypothesis. Personality and Social Psychology Bulletin, 33(8), 1167-1183.
https://doi.org/10.1177/0146167207303022
Frederick, D. A., & Jenkins, B. N. (2015). Height and body mass on the mating market: Associations
with number of sex partners and extra-pair sex among heterosexual men and women aged 18–
65. Evolutionary Psychology, 13(3). https://doi.org/10.1177%2F1474704915604563
Galis, F., Ten Broek, C., Dongen, S., & Wijnaendts, L. (2010). Sexual Dimorphism in the Prenatal
Digit Ratio ( 2D: 4D). The Official Publication of the International Academy of Sex Research,
39(1), 57-62. https://doi.org/10.1007/s10508-009-9485-7
Gallup, A. C., White, D. D., & Gallup Jr, G. G. (2007). Handgrip strength predicts sexual behavior,
body morphology, and aggression in male college students. Evolution and Human
Behavior, 28(6), 423-429. https://doi.org/10.1016/j.evolhumbehav.2007.07.001
Gat, A. (2015). Proving communal warfare among hunter‐gatherers: The quasi‐rousseauan error.
Evolutionary Anthropology: Issues, News, and Reviews, 24(3), 111-126.
https://doi.org/10.1002/evan.21446
Genovese, J. E. (2008). Physique correlates with reproductive success in an archival sample of
delinquent youth. Evolutionary Psychology, 6(3).
https://psycnet.apa.org/doi/10.1177/147470490800600301
Gettler, L. T., Kuo, P. X., Rosenbaum, S., Avila, J. L., McDade, T. W., & Kuzawa, C. W. (2019).
Sociosexuality, testosterone, and life history status: prospective associations and longitudinal
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
(which was not certified by peer review) is the author/funder. It is made available under a CC-BY-NC-ND 4.0 International license.

changes among men in Cebu, Philippines. Evolution and Human Behavior, 40(2), 249-258.
https://doi.org/10.1016/j.evolhumbehav.2018.11.001
Gildner, T. E. (2018). Life History Tradeoffs Between Testosterone and Immune Function among
Shuar Forager-horticulturalists of Amazonian Ecuador (Doctoral dissertation, University of
Oregon).
Glowacki, L., & Wrangham, R. (2015). Warfare and reproductive success in a tribal population.
Proceedings of the National Academy of Sciences, 112(2), 348.
https://doi.org/10.1073/pnas.1412287112
Gray, J. P., & Wolfe, L. D. (1980). Height and sexual dimorphism of stature among human societies.
American Journal of Physical Anthropology, 53(3), 441-456.
https://doi.org/10.1002/ajpa.1330530314
Hartl, E. M., Monnelly, E. P., & Elderkin, R. D. (2013). Physique and delinquent behavior: A thirty
year follow-up of William H. Sheldon's Varieties of Delinquent Youth. Academic Press.
Hammer, M. F., Mendez, F. L., Cox, M. P., Woerner, A. E., & Wall, J. D. (2008). Sex- biased
evolutionary forces shape genomic patterns of human diversity. PloS Genetics, 4(9).
https://doi.org/10.1371/journal.pgen.1000202
Harries, M., Hawkins, S., Hacking, J., & Hughes, I. (1998). Changes in the male voice at puberty:
vocal fold length and its relationship to the fundamental frequency of the voice. J. Laryngol.
Otol., 112(5), 451-454. https://doi.org/10.1017/S0022215100140757
Haselhuhn, M. P., Ormiston, M. E., & Wong, E. M. (2015). Men’s facial width-to-height ratio predicts
aggression: A meta-analysis. PLoS ONE, 10(4), e0122637.
https://doi.org/10.1371/journal.pone.0122637
Hill, A. K., Bailey, D. H., & Puts, D. A. (2016). Gorillas in our midst? Human sexual dimorphism and
contest competition in men. In On human nature (pp. 235-249). Academic Press.
https://doi.org/10.1016/B978-0-12-420190-3.00015-6
Hill, A. K., Hunt, J., Welling, L. L. M., Cardenas, R. A., Rotella, M. A., Wheatley, J. R., Dawood, K.,
Shriver, M. D., & Puts, D. A. (2013). Quantifying the strength and form of sexual selection on
men's traits. Evolution and Human Behavior, 34(5), 334-341.
https://doi.org/10.1016/j.evolhumbehav.2013.05.004
Holmboe, S. A., Priskorn, L., Jørgensen, N., Skakkebaek, N. E., Linneberg, A., Juul, A., & Andersson,
A.-M. (2017). Influence of marital status on testosterone levels–A ten year follow-up of 1113
men. Psychoneuroendocrinology, 80, 155-161.
https://doi.org/10.1016/j.psyneuen.2017.03.010
Hoppler, S., Walther, A., La Marca‐Ghaemmaghami, P., & Ehlert, U. (2018). Lower birthweight and
left‐/mixed‐handedness are associated with intensified age‐related sex steroid decline in men.
Findings from the Men's Health 40+ Study. Andrology, 6(6), 896-902.
https://10.1111/andr.12516
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
(which was not certified by peer review) is the author/funder. It is made available under a CC-BY-NC-ND 4.0 International license.

Hughes, S. M., & Gallup, G. G. (2003). Sex differences in morphological predictors of sexual
behavior: Shoulder to hip and waist to hip ratios. Evolution and Human Behavior, 24(3), 173-
178. https://doi.org/10.1016/S1090-5138(02)00149-6
Hönekopp, J., Rudolph, U., Beier, L., Liebert, A., & Müller, C. (2007). Physical attractiveness of face
and body as indicators of physical fitness in men. Evolution and Human Behavior, 28(2), 106-
111. https://doi.org/10.1016/j.evolhumbehav.2006.09.001
Hönekopp, J., Voracek, M., & Manning, J. T. (2006). 2nd to 4th digit ratio ( 2D: 4D) and number of
sex partners: Evidence for effects of prenatal testosterone in men. Psychoneuroendocrinology,
31(1), 30-37. https://doi.org/10.1016/j.psyneuen.2005.05.009
Johnston, V. S., Hagel, R., Franklin, M., Fink, B., & Grammer, K. (2001). Male facial attractiveness:
Evidence for hormone-mediated adaptive design. Evolution and Human Behavior, 22(4), 251-
267. https://doi.org/10.1016/S1090-5138(01)00066-6
Jordan, R., Katarzyna, P., Anna, O., Julia, S., & David, R. (2018). Human listeners can accurately
judge strength and height relative to self from aggressive roars and speech. iScience, 4, 273-
280.
Kirchengast, S., & Winkler, E. M. (1995). Differential reproductive success and body dimensions in
Kavango males from urban and rural areas in northern Namibia. Human Biology, 291-309.
Klimas, C., Ehlert, U., Lacker, T. J., Waldvogel, P., & Walther, A. (2019). Higher testosterone levels
are associated with unfaithful behavior in men. Biological psychology, 146, 107730.
https://10.1016/j.biopsycho.2019.107730
Klimek, M., Galbarczyk, A., Nenko, I., Alvarado, L. C., & Jasienska, G. (2014). Digit ratio (2D: 4D)
as an indicator of body size, testosterone concentration and number of children in human
males. Annals of Human Biology, 41(6), 518-523. https://10.3109/03014460.2014.902993
Kordsmeyer, T. L., Hunt, J., Puts, D. A., Ostner, J., & Penke, L. (2018). The relative importance of
intra- and intersexual selection on human male sexually dimorphic traits. Evolution and
Human Behavior. https://doi.org/10.1016/j.evolhumbehav.2018.03.008
Kordsmeyer, T. L., & Penke, L. (2017). The association of three indicators of developmental
instability with mating success in humans. Evolution and Human Behavior, 38(6), 704-713.
https://doi.org/10.1016/j.evolhumbehav.2017.08.002
Krzyżanowska, M., Mascie‐Taylor, C. N., & Thalabard, J. C. (2015). Is human mating for height
associated with fertility? Results from a british national cohort study. American Journal of
Human Biology, 27(4), 553-563. https://doi.org/10.1002/ajhb.22684
Kurzban, R., & Weeden, J. (2005). HurryDate: Mate preferences in action. Evolution and Human
Behavior, 26(3), 227-244. https://psycnet.apa.org/doi/10.1016/j.evolhumbehav.2004.08.012
Lassek, W. D., & Gaulin, S. J. C. (2009, Sep). Costs and benefits of fat-free muscle mass in men:
relationship to mating success, dietary requirements, and native immunity. Evolution and
Human Behavior, 30(5), 322-328. https://doi.org/10.1016/j.evolhumbehav.2009.04.002
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
(which was not certified by peer review) is the author/funder. It is made available under a CC-BY-NC-ND 4.0 International license.

Lee, T. G., Thomas, W. M., Alan, B. F., & Christopher, W. K. (2011). Longitudinal evidence that
fatherhood decreases testosterone in human males. Proceedings of the National Academy of
Sciences, 108(39), 16194. https://doi.org/10.1073/pnas.1105403108
Little, A. C. (2015). Attraction and human mating. In Evolutionary perspectives on social psychology
(pp. 319-332). Springer, Cham.
Little, B. B., Malina, R. M., Buschang, P. H., & Little, L. R. (1989). Natural selection is not related to
reduced body size in a rural subsistence agricultural community in southern Mexico. Human
Biology, 287-296.
Little, A. C., Třebický, V., Havlíček, J., Roberts, S. C., & Kleisner, K. (2015). Human perception of
fighting ability: Facial cues predict winners and losers in mixed martial arts fights. Behavioral
Ecology, 26(6), 1470-1475. https://doi.org/10.1093/beheco/arv089
Loehr, J., & O'Hara, R. B. (2013). Facial morphology predicts male fitness and rank but not survival in
Second World War Finnish soldiers. Biology letters, 9(4), 20130049.
https://10.1098/rsbl.2013.0049
Longman, D. P., Surbey, M. K., Stock, J. T., & Wells, J. C. (2018). Tandem androgenic and
psychological shifts in male reproductive effort following a manipulated “win” or “loss” in a
sporting competition. Human Nature, 29(3), 283-310. https://doi.org/10.1007/s12110-018-
9323-5
Luevano, V. X., Merkling, K., Sanchez-Pinelo, J. J., Shakeshaft, M., & Velazquez, M. L. (2018,
April). Facial width-to-height ratio, psychopathy, sociosexual orientation, and accepting
detection-risk in extra-pair relationships. Poster presented at the annual meeting of the
Western Psychological Association, Portland, OR.
Lukaszewski, A. W., Larson, C. M., Gildersleeve, K. A., Roney, J. R., & Haselton, M. G. (2014).
Condition-dependent calibration of men’s uncommitted mating orientation: evidence from
multiple samples. Evolution and Human Behavior, 35(4), 319-326.
https://psycnet.apa.org/doi/10.1016/j.evolhumbehav.2014.03.002
Maestripieri, D., Klimczuk, A., Traficonte, D., & Wilson, M. C. (2014). Ethnicity-related variation in
sexual promiscuity, relationship status, and testosterone levels in men. Evolutionary
Behavioral Sciences, 8(2), 96. https://psycnet.apa.org/doi/10.1037/h0099130
Manning, J. T. (2002). Digit ratio: A pointer to fertility, behavior, and health.
Manning, J. T., & Fink, B. (2008). Digit ratio (2D: 4D), dominance, reproductive success, asymmetry,
and sociosexuality in the BBC Internet Study. American Journal of Human Biology, 20(4),
451-461. https://10.1002/ajhb.20767
Manson, J. H., Wrangham, R. W., Boone, J. L., Chapais, B., Dunbar, R. I. M., Ember, C. R., Irons,
W., Marchant, L. F., McGrew, W. C., Nishida, T., Paterson, J. D., Smith, E. A., Stanford, C.
B., & Worthman, C. M. (1991). Intergroup aggression in chimpanzees and humans [and
comments and replies]. Current Anthropology, 32(4), 369-390. https://doi.org/10.1086/203974
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
(which was not certified by peer review) is the author/funder. It is made available under a CC-BY-NC-ND 4.0 International license.

Marczak, M., Misiak, M., Sorokowska, A., & Sorokowski, P. (2018). No sex difference in digit ratios
(2D: 4D) in the traditional Yali of Papua and its meaning for the previous hypotheses on the
inter‐populational variability in 2D: 4D. American Journal of Human Biology, 30(2).
https://doi.org/10.1002/ajhb.23078
McIntyre, M., Gangestad, S. W., Gray, P. B., Chapman, J. F., Burnham, T. C., O'Rourke, M. T., &
Thornhill, R. (2006). Romantic involvement often reduces men's testosterone levels--but not
always: The moderating role of extrapair sexual interest. Journal of personality and social
psychology, 91(4), 642. https://doi.org/10.1037/0022-3514.91.4.642
Međedović, J., & Bulut, T. (2019). A life-history perspective on body mass: Exploring the interplay
between harsh environment, body mass, and mating success. Evolutionary Behavioral
Sciences, 13(1), 84. https://psycnet.apa.org/doi/10.1037/ebs0000136
Mosing, M. A., Verweij, K. J., Madison, G., Pedersen, N. L., Zietsch, B. P., & Ullén, F. (2015). Did
sexual selection shape human music? Testing predictions from the sexual selection hypothesis
of music evolution using a large genetically informative sample of over 10,000
twins. Evolution and Human Behavior, 36(5), 359-366.
https://doi.org/10.1016/j.evolhumbehav.2015.02.004
Muehlenbein, M. P., & Bribiescas, R. G. (2005). Testosterone‐ mediated immune functions and male
life histories. American Journal of Human Biology, 17(5), 527-558.
https://doi.org/10.1002/ajhb.20419
Muller, U., & Mazur, A. (1997). Facial dominance in Homo sapiens as honest signaling of male
quality. Behavioral Ecology, 8(5), 569-579. https://doi.org/10.1093/beheco/8.5.569
Nagelkerke, N. J., Bernsen, R. M., Sgaier, S. K., & Jha, P. (2006). Body mass index, sexual behaviour,
and sexually transmitted infections: an analysis using the NHANES 1999–2000 data. BMC
Public Health, 6(1), 199. https://doi.org/10.1186/1471-2458-6-199
Nettle, D. (2002). Height and reproductive success in a cohort of British men. Human Nature, 13(4),
473-491. https://doi.org/10.1007/s12110-002-1004-7
Nowak, J., Pawłowski, B., Borkowska, B., Augustyniak, D., & Drulis-Kawa, Z. (2018). No evidence
for the immunocompetence handicap hypothesis in male humans. Scientific Reports (Nature
Publisher Group), 8(1), 1-11. https://doi.org/10.1038/s41598-018-25694-0
Pawlowski, B., G Boothroyd, L., I Perrett, D., & Kluska, S. (2008). Is female attractiveness related to
final reproductive success?. Collegium antropologicum, 32(2), 457-460.
Pawlowski, B., Dunbar, R. & Lipowicz, A. (2000). Tall men have more reproductive
success. Nature, 403(156). https://doi.org/10.1038/35003107
Penke, L., & Asendorpf, J. B. (2008). Beyond global sociosexual orientations: A more differentiated
look at sociosexuality and its effects on courtship and romantic relationships. Journal of
Personality and Social Psychology, 95(5), 1113-1135. https://doi.org/10.1037/0022-
3514.95.5.1113
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
(which was not certified by peer review) is the author/funder. It is made available under a CC-BY-NC-ND 4.0 International license.

Peters, M., Simmons, L. W., & Rhodes, G. (2008). Testosterone is associated with mating success but
not attractiveness or masculinity in human males. Animal Behaviour, 76(2), 297-303.
https://psycnet.apa.org/doi/10.1016/j.anbehav.2008.02.008
Plavcan, J. M. (2001). Sexual dimorphism in primate evolution. American Journal of Physical
Anthropology, 116(S33), 25-53. https://doi.org/10.1002/ajpa.10011
Plavcan, J. M. (2012). Body size, size variation, and sexual size dimorphism in early Homo. Current
Anthropology, 53(S6), S409-S423. https://doi.org/10.1086/667605
Pollet, T. V., van der Meij, L., Cobey, K. D., & Buunk, A. P. (2011). Testosterone levels and their
associations with lifetime number of opposite sex partners and remarriage in a large sample of
American elderly men and women. Hormones and Behavior, 60(1), 72-77.
https://10.1016/j.yhbeh.2011.03.005
Polo, P., Muñoz‐Reyes, J. A., Pita, M., Shackelford, T. K., & Fink, B. (2019). Testosterone‐dependent
facial and body traits predict men's sociosexual attitudes and behaviors. American Journal of
Human Biology, 31(3). https://10.1002/ajhb.23235
Price, M. E., Pound, N., Dunn, J., Hopkins, S., & Kang, J. (2013). Body shape preferences:
Associations with rater body shape and sociosexuality. PLoS One, 8(1).
https://10.1371/journal.pone.0052532
Prokop, P., & Fedor, P. (2011). Physical attractiveness influences reproductive success of modern
men. Journal of ethology, 29(3), 453. https://doi.org/10.1007/s10164-011-0274-0
Prokop, P., & Fedor, P. (2013). Associations between body morphology, mating success and mate
preferences among Slovak males and females. Anthropologischer Anzeiger, 70(2), 121-135.
https://doi.org/10.1127/0003-5548/2013/0284
Puts, D. (2016). Human sexual selection. Current Opinion in Psychology, 7(C), 28-32.
https://doi.org/10.1016/j.copsyc.2015.07.011
Puts, D. A., & Aung, T. (2019). Does men’s voice pitch signal formidability? A reply to Feinberg et
al. Trends in Ecology & Evolution, 34(3), 189-190. https://doi.org/10.1016/j.tree.2018.12.004
Puts, D. A., Doll, L. M., & Hill, A. K. (2014). Sexual selection on human voices. In Evolutionary
Perspectives on Human Sexual Psychology and Behavior (pp. 69-86). Springer, New York,
NY.
Puts, D. A., Gaulin, S. J., & Verdolini, K. (2006). Dominance and the evolution of sexual dimorphism
in human voice pitch. Evolution and human behavior, 27(4), 283-296.
https://10.1016/j.evolhumbehav.2005.11.003
Puts, D. A., Pope, L. E., Hill, A. K., Cárdenas, R. A., Welling, L. L., Wheatley, J. R., & Breedlove, S.
M. (2015). Fulfilling desire: Evidence for negative feedback between men's testosterone,
sociosexual psychology, and sexual partner number. Hormones and behavior, 70, 14-21.
https://10.1016/j.yhbeh.2015.01.006
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
(which was not certified by peer review) is the author/funder. It is made available under a CC-BY-NC-ND 4.0 International license.

Putz, D. A., Gaulin, S. J., Sporter, R. J., & McBurney, D. H. (2004). Sex hormones and finger length:
What does 2D: 4D indicate?. Evolution and Human Behavior, 25(3), 182-199.
https://10.1016/j.evolhumbehav.2004.03.005
Pérusse, D. (1993). Cultural and reproductive success in industrial societies: Testing the relationship at
the proximate and ultimate levels. Behav Brain Sci, 16(2), 267-283.
https://doi.org/10.1017/S0140525X00029939
Rahman, Q., Korhonen, M., & Aslam, A. (2005). Sexually dimorphic 2D: 4D ratio, height, weight,
and their relation to number of sexual partners. Personality and Individual Differences, 39(1),
83-92. https://doi.org/10.1016/j.paid.2004.12.007
Rhodes, G., Simmons, L. W., & Peters, M. (2005). Attractiveness and sexual behavior: Does
attractiveness enhance mating success?. Evolution and human behavior, 26(2), 186-201.
https://doi.org/10.1016/j.evolhumbehav.2004.08.014
Richards, G., Gomes, M., & Ventura, T. (2019). Testosterone measured from amniotic fluid and
maternal plasma shows no significant association with directional asymmetry in newborn digit
ratio ( 2D: 4D). 10(3), 362-367. https://doi.org/10.1017/S2040174418000752
Roney, J. R., & Gettler, L. T. (2015). The role of testosterone in human romantic relationships.
Current Opinion in Psychology, 1, 81-86. https://doi.org/10.1016/j.copsyc.2014.11.003
Rosenfield, K. A., Sorokowska, A., Sorokowski, P., & Puts, D. A. (2020). Sexual selection for low
male voice pitch among Amazonian forager-horticulturists. Evolution and Human
Behavior, 41(1), 3-11. https://doi.org/10.1016/j.evolhumbehav.2019.07.002
Schwarz, S., Mustafić, M., Hassebrauck, M., & Jörg, J. (2011). Short-and long-term relationship
orientation and 2D: 4D finger-length ratio. Archives of sexual behavior, 40(3), 565-574.
https://10.1007/s10508-010-9698-9
Scott, E. C., & Bajema, C. J. (1982). Height, weight and fertility among the participants of the third
Harvard growth study. Human Biology, 501-516.
Scott, I. M., Clark, A. P., Josephson, S. C., Boyette, A. H., Cuthill, I. C., Fried, R. L., Gibson, M. A.,
Hewlett, B. S., Jamieson, M., Jankowiak, W., Honey, P. L., Huang, Z., Liebert, M. A.,
Purzycki, B. G., Shaver, J. H., Snodgrass, J. J., Sosis, R., Sugiyama, L. S., Swami, V., Yu, D.
W., Zhao, Y., & Penton-Voak, I. S. (2014). Human preferences for sexually dimorphic faces
may be evolutionarily novel. 111(40). https://doi.org/10.1073/pnas.1409643111
Scott, I. M. L., Clark, A. P., Boothroyd, L. G., & Penton-Voak, I. S. (2013). Do men’s faces really
signal heritable immunocompetence? Behavioral Ecology.
https://doi.org/10.1093/beheco/ars092
Sell, A., Cosmides, L., Tooby, J., Sznycer, D., Von Rueden, C., & Gurven, M. (2009). Human
adaptations for the visual assessment of strength and fighting ability from the body and face.
Proceedings: Biological Sciences, 276(1656), 575-584.
https://doi.org/10.1098/rspb.2008.1177
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
(which was not certified by peer review) is the author/funder. It is made available under a CC-BY-NC-ND 4.0 International license.

Sell, A., Hone, L., & Pound, N. (2012). The importance of physical strength to human males. An
Interdisciplinary Biosocial Perspective, 23(1), 30-44. https://doi.org/10.1007/s12110-012-
9131-2
Sell, A., Lukazsweski, A. W., & Townsley, M. (2017). Cues of upper body strength account for most
of the variance in men’s bodily attractiveness. Proceedings of the Royal Society B: Biological
Sciences, 284(1869). https://doi.org/10.1098/rspb.2017.1819
Shoup, M. L., & Gallup, G. G. (2008). Men's faces convey information about their bodies and their
behavior: What you see is what you get. Evolutionary Psychology, 6(3).
https://psycnet.apa.org/doi/10.1177/147470490800600311
Sim, K., & Chun, W. Y. (2016). The relationships of assertiveness and responsiveness to sexual
behavior. Psychologia, 59(1), 50-69.
Simmons, Z. L., & Roney, J. R. (2011). Variation in CAG repeat length of the androgen receptor gene
predicts variables associated with intrasexual competitiveness in human males. Hormones and
Behavior, 60(3), 306-312. https://doi.org/10.1016/j.yhbeh.2011.06.006
Simpson, J. A., & Gangestad, S. W. (1991). Individual differences in sociosexuality: Evidence for
convergent and discriminant validity. Journal of Personality and Social Psychology, 60(6),
870-883. https://doi.org/10.1037/0022-3514.60.6.870
Singh, D. (1993). Adaptive Significance of Female Physical Attractiveness: Role of Waist-to-Hip
Ratio. Journal of Personality and Social Psychology, 65(2), 293-307.
https://doi.org/10.1037/0022-3514.65.2.293
Slatcher, R. B., Mehta, P. H., & Josephs, R. A. (2011). Testosterone and self-reported dominance
interact to influence human mating behavior. Social Psychological and Personality Science,
2(5), 531-539. https://doi.org/10.1177/1948550611400099
Smith, R. J., & Jungers, W. L. (1997). Body mass in comparative primatology. Journal of Human
Evolution, 32(6), 523-559. https://doi.org/10.1006/jhev.1996.0122
Smith, K. M., Olkhov, Y. M., Puts, D. A., & Apicella, C. L. (2017). Hadza men with lower voice pitch
have a better hunting reputation. Evolutionary Psychology, 15(4).
https://doi.org/10.1177/1474704917740466
Sneade, M., & Furnham, A. (2016). Hand grip strength and self-perceptions of physical attractiveness
and psychological well-being. Evolutionary Psychological Science, 2(2), 123-128.
https://doi.org/10.1007/s40806-016-0042-z
Sorokowski, P., Sorokowska, A., & Danel, D. P. (2013). Why pigs are important in Papua? Wealth,
height and reproductive success among the Yali tribe of West Papua. Economics & Human
Biology, 11(3), 382-390. https://doi.org/10.1016/j.ehb.2012.02.008
Steiner, E. T. (2011). Testosterone and vasopressin in men’s reproductive behavior. (Dissertation).
Strong, H. L. (2014). Association of prenatal androgen exposure with attention and sociosexual
orientation. (Doctoral dissertation).
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
(which was not certified by peer review) is the author/funder. It is made available under a CC-BY-NC-ND 4.0 International license.

Strong, H., & Luevano, V. X. (2014, May). Prenatal androgen exposure predicts relationship-type
preference but not experience. Poster presented at the annual meeting of the Association for
Psychological Science, San Diego, CA.
Suire, A., Raymond, M., & Barkat-Defradas, M. (2018). Human vocal behavior within competitive
and courtship contexts and its relation to mating success. Evolution and Human
Behavior, 39(6), 684-691. https://doi.org/10.1016/j.evolhumbehav.2018.07.001
Swaddle, J. P., & Reierson, G. W. (2002). Testosterone increases perceived dominance but not
attractiveness in human males. Proceedings of the Royal Society B: Biological Sciences,
269(1507), 2285-2289. https://doi.org/10.1098/rspb.2002.2165
Tao, H. L., & Yin, C. C. (2016). Height, partners and offspring: Evidence from Taiwan. Journal of
Biosocial Science, 48(5), 593-615. https://10.1017/S0021932015000346
Tovée, M., Maisey, D., Vale, E., & Cornelissen, P. (1999). Characteristics of male attractiveness for
women. The Lancet, 353(9163), 1500-1500. https://doi.org/10.1016/S0140-6736(99)00438-9
van Anders, S. M., Hamilton, L. D., & Watson, N. V. (2007). Multiple partners are associated with
higher testosterone in North American men and women. Hormones and Behavior, 51(3), 454-
459. https://doi.org/10.1016/j.yhbeh.2007.01.002
Van Dongen, S., & Sprengers, E. (2012). Hand grip strength in relation to morphological measures of
masculinity, fluctuating asymmetry and sexual behaviour in males and females. Sex
Hormones. InTech, 293-306.
Varella, M. A. C., Valentova, J. V., Pereira, K. J., & Bussab, V. S. R. (2014). Promiscuity is related to
masculine and feminine body traits in both men and women: Evidence from Brazilian and
Czech samples. Behavioural Processes, 109, 34-39.
https://doi.org/10.1016/j.beproc.2014.07.010
Von Rueden, C., Gurven, M., & Kaplan, H. (2011). Why do men seek status? Fitness payoffs to
dominance and prestige. Proceedings of the Royal Society B: Biological Sciences, 278(1715),
2223-2232. https://dx.doi.org/10.1098%2Frspb.2010.2145
Von Rueden, C. R., & Jaeggi, A. V. (2016). Men’s status and reproductive success in 33 nonindustrial
societies: Effects of subsistence, marriage system, and reproductive strategy. Proceedings of
the National Academy of Sciences, 113(39), 10824-10829.
https://doi.org/10.1073/pnas.1606800113
Voracek, M., Pum, U., & Dressler, S. G. (2010). Investigating digit ratio (2D: 4D) in a highly male‐
dominated occupation: The case of firefighters. Scandinavian Journal of Psychology, 51(2),
146-156. https://doi.org/10.1111/j.1467-9450.2009.00758.x
Walther, A., Philipp, M., Lozza, N., & Ehlert, U. (2016). The rate of change in declining steroid
hormones: a new parameter of healthy aging in men?. Oncotarget, 7(38), 60844.
https://doi.org/10.18632/oncotarget.11752
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.06.980896. this version posted March 8, 2020. The copyright holder for this preprint
(which was not certified by peer review) is the author/funder. It is made available under a CC-BY-NC-ND 4.0 International license.

Walther, A., Philipp, M., Lozza, N., & Ehlert, U. (2017). Emotional support, depressive symptoms,
and age-related alterations in male body composition: cross-sectional findings from the men's
health 40+ study. Frontiers in psychology, 8, 1075. https://doi.org/10.3389/fpsyg.2017.01075
Walther, A., Mahler, F., Debelak, R., & Ehlert, U. (2017). Psychobiological protective factors
modifying the association between age and sexual health in men: findings from the men’s
health 40+ study. American Journal of Men's Health, 11(3), 737-747.
https://doi.org/10.1177/1557988316689238
Walther, A., Waldvogel, P., Noser, E., Ruppen, J., & Ehlert, U. (2017). Emotions and Steroid
Secretion in Aging Men: A Multi—Study Report. Frontiers in Psychology, 8, 1722.
https://dx.doi.org/10.3389%2Ffpsyg.2017.01722
Waynforth, D. (1998). Fluctuating asymmetry and human male life-history traits in rural
Belize. Proceedings of the Royal Society of London. Series B: Biological Sciences, 265(1405),
1497-1501. https://dx.doi.org/10.1098%2Frspb.1998.0463
Weeden, J., & Sabini, J. (2007). Subjective and objective measures of attractiveness and their relation
to sexual behavior and sexual attitudes in university students. Archives of Sexual Behavior,
36(1), 79-88. https://doi.org/10.1007/s10508-006-9075-x
Weston, E. M., Friday, A. E., & Liò, P. (2007). Biometric evidence that sexual selection has shaped
the hominin face. PloS one, 2(1), e710.
Winkler, E. M., & Kirchengast, S. (1994). Body dimensions and differential fertility in! Kung San
males from Namibia. American Journal of Human Biology, 6(2), 203-213.
https://doi.org/10.1002/ajhb.1310060208
Xu, Y., Norton, S., & Rahman, Q. (2018). Early life conditions, reproductive and sexuality-related life
history outcomes among human males: A systematic review and meta-analysis. Evolution and
Human Behavior, 39(1), 40-51. https://doi.org/10.1016/j.evolhumbehav.2017.08.005
Zaidi, A. A., White, J. D., Mattern, B. C., Liebowitz, C. R., Puts, D. A., Claes, P., & Shriver, M. D.
(2019). Facial masculinity does not appear to be a condition-dependent male ornament and
does not reflect MHC heterozygosity in humans. Proceedings of the National Academy of
Sciences of the United States, 116(5), 1633. https://doi.org/10.1073/pnas.1808659116