Oppositional defiant disorder (ODD) has historically been considered a male problem, and factors that account for the development of ODD in girls are less well understood. Boys are at least 10 times more likely than girls to develop ODD and conduct disorder that emerges early in childhood and persists into adulthood. Prior to adolescence, boys commonly show higher prevalence rates of ODD than girls, but during adolescence the prevalence of ODD is nearly equal for both sexes. There are indications that gender and sex differences (with sex referring to biological status and gender referring to culturally assigned characteristics of biological status) in the prevalence of these problems do not emerge until after 6 years of age, when more boys show overt forms of disruptive behavior ...