A statistically significant interaction may be due to either gene-environment correlation (rGE), G × E or their combination because unresolved rGE may con-found the detection of G × E. rGE occurs because parents and their children share their genes and home environments. Therefore, genetic differences between parents may contribute to environmental risk in their offspring. One taxonomy differentiates between passive, active and evocative forms of rGE (Plomin et al. 1977; Scarr & McCartney, 1983). Passive rGE is defined as children receiving genotypes that are correlated with their family environment. Evocative rGE refers to a situation where the child’s genotype and behavior elicit parental, familial or teacher responses such as neglect. Active rGE refers to individuals who seek out environments that correspond to their genetically influenced traits. rGE may play a role in CD development because (1) diagnosis of parental antisocial personality disorder (ASP) is associated with neglect of children in the household (APA, 1994), (2) ASP is a heritable disorder (Lyons et al. 1995), and (3) passive (Ge et al. 1996; Meyer et al. 2000) and evocative (O’Connor et al. 1998; Riggins-Caspers et al. 2003) rGE have been identified in the etiology of CD.
