to influence a variety of behavioral outcomes, making it a natural extension of the project to add genotypic data. The rich, longitudinal assessments of the Child Development Project (CDP) offered special advantages for studying the pathways by which genetic factors influence behavioral development. One of the first genes we genotyped was GABRA2, a gene originally identified as associated with alcohol dependence in the collaborative study of the genetics of alcoholism (Edenberg et al., 2004), the largest gene identification project currently in existence for alcohol dependence, on which Danielle M. Dick is a collaborator. The association with adult alcohol dependence was subsequently replicated in many independent samples from around the world (Enoch, 2008). Based on the twin literature indicating that childhood behavior problems and adult alcohol dependence overlap largely due to shared genetic factors (Slutske et al., 1998), we hypothesized that GABRA2 would be associated with behavior problems at earlier stages of development. We also hypothesized that the association between the gene and behavior problems would be moderated by parental monitoring, based on our work in the Finnish twin studies showing that parental monitoring moderates the importance of genetic effects (Dick et al., 2007b). These hypotheses were supported: GABRA2 was associated
