Twin studies are not the only place from which to draw hypotheses about environmental influences that are likely to moderate genetic effects. The developmental literature contains a wealth of studies demonstrating differential effects of the environment across children with differing temperaments and/or who differ on family history. Because temperament and family history both provide information about the child’s genetic predisposition, these kinds of interactions can also serve as starting points for developing hypotheses about gene-environment interaction effects associated with specific genes. In addition to the twin evidence suggesting that parental monitoring moderated the importance of genetic effects, numerous studies in the developmental literature suggest the importance of this construct in moderating associations between early temperament/family history and the subsequent development of child behavior problems. For example, Bates and colleagues found that across two independent samples, a difficult childhood temperament was related to the subsequent development of externalizing behavior, but only in the context of lower parental control (Bates et al. 1998). Further, Molina and colleagues have found that density of family history of alcoholism is related to the development of
