items on health behaviors such as alcohol use and abuse. Here we focus on data from the age 14 assessment (88% response rate), which included questions about alcohol use, parental knowledge, peer deviance, and stressful life events. The sample used for these analyses contains 803 monozygotic (MZ) twin pairs (409 female pairs and 394 male pairs) and 825 same-sex dizygotic (DZ) twin pairs (386 female-female pairs and 436 male-male pairs). Female and male twin pairs were collapsed across zygosity in modeling consistent with previously published papers, since these analyses were intended as a follow-up to that work.
