In 2000, 16 percent of arrests for forcible rape and 19 percent of arrests for all other sex offenses involved youths under 18 years old. Juveniles that commit sexual offenses and become known to the system may represent only a small proportion of those that have committed such offenses. The characteristics of a substantial number of juveniles that have committed sex offenses do not differ significantly from juveniles that commit other types of offenses, although subgroups may differ. Girls are targeted most frequently, however boys represent up to 25 percent of some victim samples. Victims usually are substantially younger than the youth that offended. Victims are usually relatives or acquaintances; rarely are they strangers. Babysitting frequently provides the opportunity to offend. Juveniles that have offended typically are less physically violent than adult sex offenders. Some of the “triggers” that have been described as related to sex offending include anger, boredom, and family problems. Non-sexual criminal and antisocial behaviors frequently are observed in juveniles that have sexually offended. Approximately half of adult sex offenders began their sexually abusive behavior before adulthood. Childhood experiences of being physically abused, being neglected, and witnessing family violence have been associated with sexual violence in juveniles. Juveniles that have engaged in sexual offending have significant deficits in social competence; have had previous consenting sexual experiences; have experienced academic difficulties; and have cognitive distortions and attributions, such as difficulty taking another person’s perspective. Although there are few reports that have specifically addressed issues pertaining to sibling incest, it appears to be quite prevalent. Studies on adolescent girls that have committed sex offenses are relatively rare.