Criminal offending and the family environment: Swedish national high-risk home-reared and adopted-away co-sibling control study

Abstract

BackgroundCriminal offending is strongly transmitted across generations.AimsTo clarify the contribution of rearing environment to cross-generational transmission of crime.MethodUsing Swedish national registries, we identified 1176 full-sibling and 3085 half-sibling sets from high-risk families where at least one sibling was adopted and the other raised by the biological parents.ResultsRisk for criminal conviction was substantially lower in the full- and half-siblings who were adopted v. home-reared (hazard ratios (HR) = 0.56, 95% CI 0.50–0.64 and 0.60, 95% CI 0.56–0.65, respectively). The protective effect of adoption was significantly stronger in sibships with two v. one high-risk parent.ConclusionsUsing matched high-risk full- and half-siblings, we found replicated evidence that (a) rearing environment has a strong impact on risk for criminal conviction, (b) high-quality rearing environments have especially strong effects in those at high familial risk for criminal offending and (c) the protective effects of adoption are stronger for more severe crimes and for repeated offending.