Few studies have explored early predictors of problem drinking in youth, and fewer still have simultaneously considered the role of biologic, familial, and intrapersonal factors. The present study explored early life course and later life course predictors of alcohol abuse and dependence in young adulthood. Data were taken from a cohort of 2,551 mothers and their children recruited as part of the longitudinal Mater University Study of Pregnancy and its outcomes (MUSP) carried out in Brisbane, Australia, from 1981 to 1984. Data were collected prenatally and then postnatally at 6 months and at 5, 14, and 21 years. A range of biologic, familial, and intrapersonal factors was considered. A series of logistic regression models with inverse probability weighting was used to explore pathways to problem drinking from adolescence to early adulthood. For males and females, no association was found between either birth factors or childhood factors and a lifetime diagnosis of alcohol disorders at age 21 years. Externalizing symptoms and maternal factors at age 14 years were significantly associated with alcohol problems. For youth aged 14 years, maternal moderate alcohol consumption accounted for the highest percentage of attributable risk among those exposed. Results show that exposure to maternal drinking in adolescence is a strong risk factor for the development of alcohol problems in early adulthood.