Researchers Michele Ybarra of the Center for Innovative Public Health Research and Kimberly Mitchell of the Crimes Against Children Research Center at the University of New Hampshire followed American youth over the course of several years, asking the youngsters questions about their sexual behavior during that time to see if there was any indication of sexual violence early in a person's history.

What they found was startling: Nearly 10 percent of survey respondents reported perpetrating some form of sexual violence in their lifetime, with 4 percent reporting attempted or completed rape.

In fact, teenage boys and girls increasingly instigate sexual violence—and many convicted perpetrators of sexual crimes began at young ages.

Today's adult rapist may have once been a