Interpreting G × E effects as part of an intergenerational pathway is more complex than in the typical G × E study. This is because parental genetic predispositions for externalizing behavior contribute to the externalizing behavior of the adolescent through genetically- and environmentally-mediated processes (Hicks et al., 2004). Although the focus of the present intergenerational study was on the interaction of life events and adolescent GABRA2 genotype to predict externalizing, it is possible that life events and parental GABRA2 genotype may interact to predict the types of sub-optimal parenting practices (e.g., participating in coercive interactions) that in turn contribute to adolescents’ externalizing. Although we are unable to examine this possibility in the present study, we believe that these types of process-oriented hypotheses are important for understanding the intergenerational transmission of externalizing behavior, and the interaction of environmental and genetic factors (both parental and offspring) (Klahr & Burt, 2014).
