Goofs

When Joey is talking to Lydia's mother on the phone he tells her he is 25 years old. In the episode before this one, The One with the Ick Factor (1995), Monica states that she is 26 years old. Later on in season 7, it is stated that Joey is 31 years old which is the same year Rachel turns 30. Rachel and Monica are the same age which makes Joey older than both of them - which makes the fact that Joey tells Lydia's mom that he's 25, a mistake.

Actually, there is no correlation between TV time and real time. This is especially true for Friends, as the first episode of a new season often takes place the day after of the last episode in the prior season.

A sign that can be seen when the door of Carol's room is opened says "nusery" instead of "nursery"

During scene when Ross, Phoebe and Susan are locked in the broom closet, there's a close up of them trying a credit card to swipe the lock. The door clearly has the snib to unlock it, so they should have been able to get out.

Ross comments on the parts of the baby he is seeing being born: head, the shoulders, the fingers, then the chest, then "definitely a boy". In real life, once the baby's head then shoulders have passed through the vulva, the rest emerges so quickly that there is no way Ross could have slowly commented and described each part and probably would have missed the genitalia.

At 19:12 on DVD version Susan says, "Look at that," but Carol has a bed sheet covering her, so there is no way for Susan to look at the baby.