Revisiting the effects of adult roles on criminal offending: A genetically-informed study

AbstractTransitions to adult roles – such as employment, marriage, and parenthood - have played a central role in theories explaining the decrease in criminal behavior during adulthood. Studies indeed often found negative relationships between these adult roles and offending, but causal inference is usually impossible due to selection effects. The current study uses discordant sibling and twin models to control for confounders that are shared within families (i.e., genetic and shared environmental confounders). Register data of 1,203,178 individuals born in the Netherlands between 1983 and 1989 were analyzed. Among them, 15.1% had committed at least one crime between age 18–30. The analyses focus on the month in which the first crime was committed, on average at age 21.69. In this focal month, offenders were found to be significantly more often single, unemployed and parent than non-offenders. However, when comparisons were made within pairs of same-sex siblings and same-sex twins, the effect sizes of employment status and parenthood decreased and became non-significant. The association between relationship status and criminal offending remained negative and significant, in line with a causal explanation. These results illustrate that effect sizes may be overestimated and wrong conclusions may be drawn when unmeasured familial confounders are ignored.