conducted separately for maternal and paternal measures. Two such tests were significant: effects of paternal maximum consumption on early drug use and on twin maximum consumption differed by age cohort, χ2 = 4.60, p = .032, and χ2 = 7.25, p = .007, respectively. In both cases, effects were stronger in the older cohort. We assessed interactions between maternal and paternal status separately in each cohort for these two outcomes.
