Parameter estimates and significance values for all analyses are provided in Table 1. There were no main effects of genotype on the overall latent factor for externalizing behavior (p=0.255). We did observe a significant main effect of physical discipline (p<0.001), such that increases in such aggression were associated with increases in externalizing behavior. The effect of GxE interaction was not statistically significant (p=0.135), but the effect was in the expected direction; i.e., as levels of physical discipline increased, males carrying the risk allele had higher mean latent externalizing factor scores than did their counterparts who did not carry the risk allele (Figure 1A). These trends were also evident in main effects models run separately by genotype, in which the parameter estimate (β) of physical discipline was higher for males carrying a low-activity allele (β=0.473) than for those carrying a high-activity allele (β=0.333).
