MAOA and male antisocial behavior: A review

• Maleness is the most robust predictor of antisocial behavior.
• The low activity form of the monoamine oxidase-A gene (MAOA-L) is the most well-supported link between a genetic variation and antisocial behavior.
• Male are three times more likely than females to have the MAOA-L variation.

Of all the risk factors for the development of antisocial behavior, “maleness” is by far the most robust predictor. Among the numerous biological factors that have been identified as increasing risk for antisocial behavior, one of the most well-supported has inexplicably received very little attention with regard to implications for explaining why maleness is such a robust predictor. That factor is the low activity form of the monoamine oxidase-A gene. A major reason for this inattention to the MAOA-L gene appears to be the failure to appreciate that its location on the X chromosome reflects the enormous biological disadvantage of the male compared to the female. This article, after presenting a brief overview of the research which establishes that MAOA-L is one of the most well-supported biological risk factors for antisocial behaviors, explained how the enormous male biological disadvantage related to the sex difference in the prevalence of MAOA-L and thus helped explain why maleness is the most robust predictor of antisocial behavior.