The one-child family and violent criminality: A 31-year follow-up study ofthe northern Finland 1966 birth cohort

Objective: Serious defects in social skills acquired during childhood may b e associated with aggressive behavior in later life. The authors studied wh ether being an only child was associated with criminality in adulthood and, secondly, if parental factors increased the putative risk. Method: The authors used an unselected, prospectively collected large birth cohort. Data on crimes were linked with being an only child as well as wit h perinatal risk and maternal and paternal psychological risk factors among male subjects. Results: The risk for violent crimes later in life was elevated among the o nly children. If perinatal or parental risks were combined with being an on ly child, the odds ratios for violent offending increased four-fold to eigh t-fold. A corresponding risk increase between being an only child and nonvi olent offending was not detected. Conclusions: These results support the hypothesis that growing up as an onl y child is associated with violent criminality among male subjects.