Minor physical anomalies are considered indicators of disruption in fetal development. They have been found to predict behavioral problems and psychiatric disorders. This study examined the extent to which minor physical anomalies, family adversity, and their interaction predict violent and nonviolent delinquency in adolescence.
Minor physical anomalies were assessed in a group of 170 adolescent boys from low socioeconomic status neighborhoods of Montréal. The boys had been enrolled in a longitudinal study since their kindergarten year, when an assessment of family adversity had been made on the basis of familial status and the parents' occupational prestige, age at the birth of the first child, and educational level. Adolescent delinquency was measured by using self-reported questionnaires and a search of official crime records.
Results from logistic regression analyses indicated that both the total count of minor physical anomalies and the total count of minor physical anomalies of the mouth were significantly associated with an increased risk of violent delinquency in adolescence, beyond the effects of childhood physical aggression and family adversity. Similar findings were not found for nonviolent delinquency.
Children with a higher count of minor physical anomalies, and especially a higher count of anomalies of the mouth, could be more difficult to socialize for different and additive reasons: they may have neurological deficits, and they may have feeding problems in the first months after birth. Longitudinal studies of infants with minor physical anomalies of the mouth are needed to understand the process by which they fail to learn to inhibit physical aggression.