We utilized data on child gene polymorphism, child sex, the quantitative variable of childcare quality, and the child outcome variable of social skills. The two-group gene categorization for this analysis was based onexon-3 VNTR in the dopamine D4 receptor gene (DRD4). Prior research (e.g., Bakermans-Kranenburg & van IJzendoorn, 2006; Belsky & Pluess, 2009) suggests that presence of a 7-repeat on DRD4 is a risk factor for many developmental outcomes. The dummy variable for DRD4 was coded as D2 = 0 or 1 for absence or presence, respectively, of a 7-repeat. Of 438 participants with genotype data, 95 (22%) had the 7-repeat on DRD4, so constituted the high-risk/malleability group. The remaining 343 participants (78%) did not have the 7-repeat, so constituted the low-risk/malleability group. Child sex was coded as 0 = female, 1 = male; the sample was almost equally divided on sex (51.8% female).
