Overall the findings indicate strong intergenerational linkages across three generations. However, they are linkages conditioned by gender and continuing contact. In focusing on early onset substance use, intergenerational continuity in substance use was only observed and found for G2 or Generation 2 females and their children. With almost all G1 or Generation 1 respondents in the study being female, it meant that the substance use of G1 mothers increased the risk of use for their daughters, but not their sons. In investigating early onset substance use in the third generation, use by children of G2 mothers was significantly influenced by both G2 substance use and by G1 substance use. For children of G2 fathers, however, neither prior generation’s substance use was significantly related to G3 or Generation 3 use. This strongly suggests that continuing contact with the child is almost essential for the intergenerational transfer for risk. Utilizing both the Rochester Youth Development Study for data on G1 and adolescent G2 respondents and the Rochester Intergenerational Study for data on adult G2 and G3 respondents addressed the fundamental question on the origins of substance use. Tables and references