The intervention consisted of two kinds of assistance: parenting training and social skills training for the boys. Several family traits, including level of parental education, number of siblings, day care experience, and parents' age at the time of the child's birth, were linked with violent behavior in kindergarten-aged boys. This longitudinal study compared boys who were temporarily violent in kindergarten, boys who continued their aggression throughout primary school, and boys who were never violent. Boys who exhibited continuing aggression had significantly more academic and social adaptation problems than the other groups. The effects of the intervention program appeared to be positive; boys who participated in it were less likely to fight, to steal from home, or to have learning problems. However, there were no differences between the experimental and control and observation groups on a number of variables indicative of adaptation difficulties. The research on this cohort is continuing as the boys reach the age (13 to 18) in which they are most likely to commit delinquent acts. 4 figures and 20 notes (Author abstract modified)