When Kristina and Michelle Kennedy were in college, they found out that Diane Keaton was doing a book signing in Southampton, New York. They showed up and when Keaton was doing signings, they placed the photo for Keaton to sign. Keaton remarked on the photo that she'd been thinking about the twins the other day. When she went to sign, she looked at the sisters, back to the photo and realized it was them. Keaton subsequently got up and hugged them both. The sisters later went onto become teachers.
Producer Nancy Meyers once said of the casting in this film of actor Sam Shepard: "From the beginning, we were told to forget trying to get Sam to portray a character who doesn't enter the film until the third act. But we sent the script care of a True Value Hardware Store in Virginia, and two days later he said he'd do it."
Early movie of Christopher Noth. He played one of the tourists who bought Keaton's gourmet baby food.
J.C. Wiatt (Diane Keaton) worked at Sloane Curtis Advertising which was the same firm in What Women Want (2000), a film directed by the writer of Baby Boom, Nancy Meyers.
Writer-producer Nancy Meyers once said of this film: "Our movie is about someone who never planned on motherhood. The comedy comes from J.C.'s ineptness to deal with this surprise. Ten years ago [c. 1977], Baby Boom (1987) would have probably starred a man, because not until recently, with the great female drive toward careerism and success, would it be believable that a woman could be so ill-prepared for motherhood."