Foetal testosterone and eye contact in 12-month-old human infants

Amniotic fluid was analysed for foetal testosterone (FT) level. Postnatally, the infants (29 girls and 41 boys) and parents were filmed at 12 months of age, and the amount of eye contact made by the infant to the parent was recorded. Girls made significantly more eye contact than boys. This replicates previous studies showing a female superiority in sociality more broadly, and eye contact in particular. The amount of eye contact varied quadratically with foetal testosterone level when data from both sexes was examined together, and when the data for the boys was examined alone. This suggests that foetal testosterone may shape the neural mechanisms underlying social development. (C) 2002 Elsevier Science Inc. All rights reserved.