The National Center for post-traumatic stress disorder, part of the U.S. Department of Veterans Affairs, said 60 percent of child sex abusers know the child they abuse -- but are not family -- and could be a friend of the family, babysitter, or neighbor.
About 3 out of 10 of those who sexually abuse children are family members of the child including fathers, grandfathers, uncles, or cousins, government officials said.
The abuser is a stranger in only about 1 out of 10 child sexual abuse cases, the center said.
Abusers are mostly men, whether the victim is a boy or a girl. Women are the abusers in about 14 percent of cases reported against boys and about 6 percent of cases reported against girls, the center said.
Child sexual abuse often involves body contact, including sexual kissing, touching and oral, anal or vaginal sex. However, showing private parts, forcing children to watch pornography, verbal pressure for sex and exploiting children as prostitutes or for pornography are sexual abuse as well, the center said.