A new study commissioned by the US Justice Department shows that more than a third of sex crimes against juveniles are committed by other minors.

The study was done by the Crimes Against Children Research Center at the University of New Hampshire, and the findings are presented in a US Department of Justice bulletin "Juveniles Who Commit Sex Offenses Against Minors."

The study shows that juveniles make up 36 percent of all sex offenders who commit crimes against minors. Seven out of eight are 12 years of age or over, with five percent under the age of nine. Ninety-three percent of juvenile sex offenders are boys. Juveniles who commit sex offenses against other kids are more likely than adult sex offenders to offend at schools, in groups, and to have more male and younger victims, the report also said.

The juvenile sex offenders study was based on 2004 law enforcement data, and comes as many states attempt to toughen penalties for adult sex offenders. States have long struggled with how to deal with juvenile offenders, whose offenses often include sexual experimentation and date rape.