Participants were drawn from two studies of Australian children of twins selected from a young adult twin panel born between 1964 and 1971 (Heath et al., 2001; Knopik et al., 2004). Following initial contact by mailed questionnaire in 1989 (thus, the “1989” cohort), twins completed diagnostic telephone interviews during 1997–2002. Pairs where at least one twin had biological children ages 7–24 and one twin met DSM-IV criteria for alcohol use disorder (AUD; operationalized as alcohol dependence (AD) in male twins and either AD or alcohol abuse (AB) in female twins) were subsequently recruited for participation in one of two coordinated follow-up studies: Mothers And Their Children (MATCH) and Parental Alcoholism and Child Environmental Risk (PACER). A random sample of control pairs, where at least one twin had biological children ages 7–24, but neither twin met criteria for AUD, was also recruited. MATCH twins were selected from female same-sex pairs from both the 1989 cohort and an older “1981” cohort described elsewhere (see Heath et al., 1997; Waldron et al., 2009). PACER twins were selected from male same- and opposite-sex pairs
