Among the subjects interviewed, more than 35 percent of black males and 25 percent of non-Hispanic white males reported that they had been involved in one or more violent acts by age 17. More than one-fifth of black females ages 15-17 and one-tenth of white females reported such involvement. An alarming new phenomenon is the increase of violence among females, often in complicity with violent males. Violence against young females by males their age is another increasing problem. Guns are involved in more than 75 percent of adolescent killings. Nevertheless, as an American Psychological Association (APA) report notes, juvenile behavior is not shaped in isolation from adult standards. The APA emphasizes that many factors contribute to violence, including severe frustrations, doing poorly in school, being stigmatized as dumb, and a lack of social skills. In addition, children who have experienced abuse and neglect while growing up learn to regard it as normal and tend to repeat the behavior with their own chldren. The role of the entertainment media in causing youth violence is a controversial topic. The APA report warns that viewing violence in movies, television, and video games increases the fear of becoming a victim of violence, resulting in an increase in self-protective behaviors and distrust of others.