Age of Onset Some studies indicate that both boys and girls tend to begin their
antisocial careers around the age of fifteen, with the average age of onset
differing by no more than six months across genders.44
Other research, however, finds that females begin offending when they are younger than males are.45 Notably, gender differences in the age of onset tend to be most pronounced for serious or aggressive types of delinquency, while less serious problem
behaviors, such as drug and alcohol - related offenses, have less gender - differentiated progressions.46