This article discusses how adolescents become violent from the perspective of human development, in which the process of formation of the child and the youth depends on diverse biological, psychological e social variables that constitute the context of life of these individuals. The ecological perspective of human development opposes simple cause-effect relations between antisocial adversities and behaviors and believes that factors such as gender, temperament, cognitive ability, age, family, social environment and culture combine in a complex way influencing the behavior of the child and the adolescent. Some conclusions point to the fact that violence in adolescence usually starts from a combination of early difficulties in relationships associated with a combination of temperamental difficulties. It is concluded that the young seem to be as bad as the social environment surrounding them.