The study included 232 boys who had been randomly selected for a treatment program designed to prevent delinquency. The boys lived in congested urban areas near Boston, and counselors visited their homes about twice a month over a period of more than 5 years. Child rearing variables included family structure, family conflict, and esteem of each parent for the other, as well as parental supervision and discipline, warmth, self-confidence, role, aggressiveness, alcoholism, and criminality. Comparisons for the impact of child rearing showed that mother's competence, father's interaction with the family, and family expectations were related to delinquency. Considered separately, poor child rearing in each of these domains reliably increased the risk of delinquency. Only 5 percent of boys reared by competent mothers in families with good parental interaction and high expectations became delinquents. In contrast, almost half of those raised by incompetent mothers in homes with poor paternal interaction and low expectations became delinquents. Although maternal behavior influenced delinquency and thus adult criminality, paternal interaction with the family had a more direct influence on the probability of adult criminal behavior. Competent mothers seemed to insulate children against criminogenic influences even in deteriorated neighborhoods. 80 references and 8 tables