A Study of Problem Behaviors in 10- to 15-Year-Old Biologically Related and Unrelated International Adoptees

Genetic and environmental influences on problem behaviors were studied in a sample of international adoptees. Parental ratings of childrens' problem behaviors were obtained with the Child Behavior Checklist (CBCL). The sample (mean age, 12.4 years) comprised a group of biological siblings (111 pairs), a group of nonbiological siblings (221 pairs), and a group of singletons (94). Nonshared environmental influences were most important for problem behaviors studied in this paper. Genetic influences were substantial for Externalizing behaviors but unimportant for Internalizing behaviors. For the C... Mehr ...