Variation in the dopamine receptor D4 gene (DRD4) has generated considerable attention in the Gene × Environment interaction (see D’Onofrio & Lahey, 2010, for a review) research literature. Several studies have demonstrated that variation in DRD4 moderates the impact of environmental exposures on an array of developmental outcomes (Bakermans-Krannenburg & van IJzendoorn, 2011; Bakermans-Kranenburg, van IJzendoorn, Mesman, Alink, & Juffer, 2008; Bakermans-Kranenburg, van IJzendoorn, Pijlman, Mesman, & Juffer, 2008; Beach, Brody, Lei, & Philibert, 2010; Belsky & Pluess, 2013; Knafo, Israel, & Ebstein, 2011). Specifically, the DRD4 7 variable number of repeats (VNTR) allele has been associated with variation in sensitivity to the social environment (see Bakermans-Kranenburg & van IJzendoorn, 2011, for a review). In brief, children who possess at least one copy of the 7-repeat allele (7+) tend to be more sensitive to contextual factors (e.g., parenting) compared to children who do not possess a 7-repeat copy (7−). Although much of this research has been cast within DST, we should emphasize that the results of these studies—that children who are 7+ show greater sensitivity to positive environments—are consistent with
