The study examined a sample of 642 boys from low- socioeconomic-status (SES) families. Paternal alcoholism was established using the Short Michigan Alcohol Screening Test. Behavioral problems (opposition, hyperactivity, inattention, physical aggression and anxiety) were assessed by teachers' reports when the boys were 6 and 12 years old. Four groups of boys were created on the basis of paternal alcoholism (nonalcoholic, alcoholic) and family structure (intact families, nonintact/father-absent families). A propensity for physical aggression and low anxiety best distinguished sons of male alcoholics (SOMAs) from non-SOMAs at both ages, even when SES was controlled. In addition, SOMAs were more oppositional and hyperactive at both ages. No significant effects were observed for family structure or age, or an interaction between these factors and paternal alcoholism in the multivariate analysis. Tables, references