Childhood adversity is defined as exposure to inter-parental violence, inconsistent parenting and parental neglect in order to capture the common features of salient risk factors of a difficult home environment, which are important to understanding the development of CD and to allow comparability between previous studies of G × E (Caspi et al. 2002; Foley et al. 2004). Exposure to inter-parental violence presents household aggression as a normative part of family relationships (Osofsky, 1995) and may be imitated, giving rise to difficulty in social adjustment outside the home (Dodge, 1986; Fergusson & Horwood, 1998). Males and females have been reported to be equally exposed to inter-parental violence (Moffitt et al. 2001b), although it is unclear whether this risk factor functions similarly in the development of CD in both groups (Herrera & McCloskey, 2001; Becker & McCloskey, 2002; Kinsfogel & Grych, 2004).
