Fourth, we found an association between child’s genetic predispositions and parental knowledge, suggestive of evocative gene-environment correlation. However, there could be additional alternative explanations, such as passive rGE. For example, this relationship could also in part indicate that parents themselves were high on externalizing symptomatology (genetically influenced characteristics), which contributed to lower levels of parental knowledge, as research suggests that parental psychopathology negatively influences parenting (Berg-Nielsen et al. 2002; Cummings et al. 2005). Future work with assessments of parental psychopathology will be needed to tease apart the pathways by which risk unfolds. Fifth, we focused only on peer substance use because it is a commonly studied aspect of peer influences on externalizing behaviors. Our sample was, however, limited in the peer measures that were collected. Future research can consider the role of broader peer influences, including delinquency and deviance.
