effects have been demonstrated for more general externalizing behavior: Genetic influences on antisocial behavior were higher in the presence of delinquent peers (Button et al. 2007) and in environments characterized by high parental negativity (Feinberg et al. 2007), low parental warmth (Feinberg et al. 2007), and high paternal punitive discipline (Button et al. 2008). Further, in an extension of the socioregional-moderating effects observed on age-18 alcohol use, we found a parallel moderating role of these socioregional variables on age-14 behavior problems in girls in a younger Finnish twin sample. Genetic influences assumed greater importance in urban settings, communities with greater migration, and communities with a higher percentage of slightly older adolescents.
