Abstract

Research with animals and humans reveals clear sex differences, favouring males, in physical aggression. Some sex differences in brain structure and function are thought to be influenced by levels of sex hormones present during different stages of development. Investigating the influence of prenatal androgens, in both the normal and abnormal range, on sex differences in children’s physical aggression could elucidate the developmental impact of prenatal androgens on this important aspect of human behaviour. The overall aims of the present study were to assess the influence of prenatal androgens on children’s physical aggression and explore the mechanisms underpinning any associations identified, focusing in particular on temperamental characteristics. Study measures were completed by a sample of 75 typically-developing children, aged between 5 and 8 years, for whom measures of testosterone (T) in amniotic fluid had been obtained. The predicted sex differences were found for physical aggression, levels of amniotic T and several of the temperament constructs. In addition, physical aggression correlated with levels of amniotic T and several of the temperament constructs. However, only inhibitory control mediated the sex difference in physical aggression. The results suggest that prenatal androgen exposure may not influence the sex difference in children’s physical aggression to the same extent as it is thought to influence other behaviours that show a sex difference, e.g., children’s play behaviour. Rather, they point to a more central role for social/environmental factors in explaining this important sex difference.