The objective of this study was to examine whether social risk factors adjusted for gender and some well-known perinatal risk factors were related to parental descriptions of deviant behaviour in 3(1/2)-year-old children. The study was a prospective cohort study of 1345 mothers enrolled during early pregnancy. Parents answered a questionnaire and children's behavioural difficulties were categorized into the following groups; "hyperactive-distractible", "hostile-aggressive" and "anxious-fearful" following a modified Behar scale. The male gender was found to be related to a description of all kinds of deviant behaviour. Having a family member experiencing employment difficulties was the factor most closely related to "hyperactive-distractible" behaviour. Familial stress due to lack of time, experience of divorce and mothers in excess of 35 years at childbirth were found to be related to "hostile-aggressive" behaviour, but male gender was the most closely related. Social disadvantage was not found to be related to "anxious-fearful" behaviour.