Genetic factors may influence the selection of peers, or may be otherwise correlated with peer identity or behavior. In fact, a longitudinal twin study found that genetic factors accounted for the entirety of the relationship between direct-report peer alcohol use and adolescent drinking (Hill, et al., 2008). However, in our sample, peer deviance did not vary by ALDH2 genotype, suggesting that it is appropriate to consider its influence as a potential environmental moderator of ALHD2 effect.
