Despite the potential importance of these findings, several important limitations must be noted. First, a primary shortcoming of this study is that our sample size is modest, which increases the likelihood that our results reflect false-positive findings (see Duncan and Keller, 2011). Although the threshold for significance was adjusted (i.e., modified α level) to attenuate the inflation of Type I error, we must emphasize the importance of independent and direct replication of these findings. Second, we must consider that parental monitoring and deviant peer affiliation are themselves likely to be genetically influenced. There is growing evidence that parental monitoring is complex, affected by both genetic and environmental factors (Neiderhiser et al., 2004). Genetic influences include the genotypic characteristics of the parents and the genetically influenced characteristics of the adolescents that influence their interactions with their parents. Similarly, twin studies indicate that genetic factors influence adolescents’ selection of peers with similar temperament and drinking patterns (Fowler et al., 2007). Because genotypic factors influence susceptibility to alcoholism as well as parental monitoring and peer selection, the association between these factors may be
