Childhood: Genes

Abstract

In the Prologue we discussed the finding that boys with one form of the MAOA gene who were also abused were six times as likely to be violent when they became adults. Neither factor on its own produced an increase in aggression; it was the combination of genes and environment that led to the striking increase in violent behaviour. In this chapter and the following one we are going to look more closely at how our heredity and environment shape our behaviour, starting here with heredity.