Predisposition to petty criminality in Swedish adoptees. III. Sex differences and validation of the male typology.

Sex differences in the inheritance of criminality were studied in 913 women and 862 men from the Stockholm Adoption Study. Our multivariate classification of genetic heterogeneity was validated in the female sample by confirmation of predictions derived from the men. The congenital antecedents of criminality were the same regardless of sex, but the congenital predisposition to criminality had to be more severe for a woman to be affected. Furthermore, the postnatal antecedents of criminality that were studied were qualitatively different in the two sexes. Prolonged institutional care and urban rearing increased the risk of criminality in women but not in men. In contrast, multiple temporary placements and low social status of the adoptive home increased the risk ot criminality in men but not women. The antecedents of petty criminality and alcohol abuse were distinct in both sexes. Cross-fostering analysis indicated that postnatal factors were more important for criminality than for alcoholism in women. We discuss the overall significance of this series of reports and make suggestions for future research.