Examined longitudinally the relationship between biological and social risk factors and aggressive behavior patterns among high-risk Australian adolescents in three groups: early-onset persistent aggression, adolescent-onset aggression, and nonaggressive behavior groups. Findings revealed that the interaction of biological and social risk factors was significantly related to early-onset persistent aggression. Gender and developmental measurement phase moderated the relationship between biosocial risks and the outcomes of early-onset persistent aggression and adolescent-onset aggression. (Author/KB)