Abstract
Prior research has reported a positive impact of adoption on developmental outcomes for children with experience of foster care. To inform decisions about permanent care arrangements, we used Swedish national population registers to create a sibling population consisting of 194 children born 1973–1982 who had been in out-of-home care (OHC) at least 5 years before adolescence but were never adopted (50% boys) and their 177 maternal birth siblings who also had been in OHC at least 5 years before their teens but were adopted before adolescence (52.5% boys). We constructed 14 outcome variables spanning social, educational, and health outcomes in adult age with information from Swedish national registers. Based on multilevel logistic random effects and fixed effects regression models (supplemented with a sensitivity analysis assessing the potential impact of unobserved confounding), results showed that adopted siblings tended to have considerably better outcomes in adult age in educational achievement, income, criminality, disability, and suicidality. Outcomes related to mental health and substance abuse were more similar, but differences pointed in the same direction. Implications for child welfare policy and practice are discussed.