(Kendler et al. 2008). For example, although studies have uniformly indicated that deviant peer affiliation exacerbates genetic influences on conduct problems/externalizing behaviors during adolescence (Cleveland et al. 2005; Button et al. 2007; Harden et al. 2008; Beaver et al. 2009; Hicks et al. 2009), a study conducted during childhood was unable to replicate these results (Burt & Klump, 2013b). Instead, genetic influences on child conduct problems appeared to be proportionally more important in the absence of deviant peer affiliation, whereas shared environmental influences were more important in the presence of deviant peer affiliation.
