Although the diathesis-stress model guides most genetically informed behavior science, the present study investigates the hypotheses derived from the differential susceptibility perspective. This model posits that those persons most vulnerable to adverse social environments are the same ones who reap the most benefit from environmental support. Using longitudinal data from a sample of several hundred African American males, we examined the manner in which variants in 3 genes—5-serotonin transporter gene (5-HTT), dopamine receptor gene (DRD4), and monoamine oxidase gene (MAOA)—modulate the effect of community and family adversity on adoption of the street code and aggression. We found strong support for the differential susceptibility perspective.