Genetic and environmental influences on antisocial behavior: A meta-analysis of twin and adoption studies

A meta-analysis of 51 twin and adoption studies was conducted to estimate the magnitude of gene tic and environmental influences on antisocial behavior. The best fitting model included moderate proportions of variance due to additive genetic influences (.32), nonadditive genetic influences (.09), shared environmental influences (.16) and nonshared envirornmental influences (.43), The magnitude of familial influences (i.e., both genetic and shared environmental influences) was lower in parent-offspring adoption studies than in both twin studies and sibling adoption studies. Operationalizition, assessment method, zygusity determination method, and age were significant moderators of the magnitude of genetic and environmental influences on antisocial behavior, but there Am no significant differences ill the magnitude of genetic and environmental influences for males and females.