or greater increased risk for AUD in sons of alcoholics even when they were adopted as infants and raised by nonalcoholic families (Goodwin et al., 1973, 1977,1974). For example, Goodwin et al. (1973) studied the drinking history of 55 adopted-out sons of alcoholics and 78 adopted-out sons of non-alcoholics. All of the sons were adopted as infants, within the first six weeks of life. Importantly, the sons of alcoholics had no knowledge that their biological parents' suffered from alcoholism. Biological sons of alcoholics who had been adopted by non-related foster families were four times as likely to become alcoholics compared to adopted sons of non-alcoholics. These seminal findings provided convincing support that part of the vulnerability to AUD was mediated by genetic factors.
