FinnTwin12 is a population-based Finnish twin sample of approximately 2,700 twin pairs; of these parental externalizing (measured when the twins were age 12), adolescent life events, adolescent externalizing behavior (both measured at age 14), and genotypic data were available for 802 twins from 478 families (297 monozygotic individuals, 497 dizygotic individuals, and 8 individuals of unknown zygosity; 52% female, 48% male). Further details about the sample and assessments can be found in Kaprio, Pulkkinen, and Rose (2002) and Knaapila et al. (2011).
