Conduct disorder (CD) symptom counts in preadolescent boys, and antisocial personality disorder (ASP) and childhood conduct disorder symptom counts in their parents, were used as dimensional measures of behavioral deviation. A significant correlation was found for CD and ASP symptom counts between the two parents and between CD symptom counts of the children and parental CD and ASP symptom counts. Although socioeconomic level correlated negatively with parental symptom counts, no association was observed between parental socioeconomic status and children's CD symptom counts. Saliva cortisol level in the children was negatively associated with their CD symptom count and with their fathers' ASP count. Cortisol level was also lower among sons whose fathers had CD as children and subsequently developed ASP compared with the cortisol level in sons whose fathers either did not have any Axis I psychiatric disorder or did not develop ASP.