Does parental separation moderate the heritability of health risk behavior among adolescents?

Social influences on adolescents’ health risk behavior are well documented, but little is known about the interaction of parental separation with genetic sensitivities. Using data from a German sample of 1,824 twins, this study examines whether family living arrangements moderate the extent to which health risk behavior among adolescents is influenced by genetic predispositions. Derived from variance decomposition moderator models, the results provide evidence of a significantly larger genetic contribution to smoking among adolescents living in single-mother families than among adolescents living with both parents, but not of the moderation of heritability for drug use and excessive alcohol consumption. Thus, these findings indicate that the unfolding of genetic risk is increased for smoking, but not for other substances. However, the significantly stronger influences of individual experiences of drug use observed in single-mother families reveal the overall vulnerability of families who have experienced parental separation.