mínúts sjö ...One report suggested that around 5% of children are involved in sibling sexual abuse.1 Estimates suggest that sexual abuse perpetrated by siblings may be up to three times as common as sexual abuse by a parent.2he average age of a juvenile sex offender is 15 years old. Most registered sex offenders carry out their first offense before age of 18.5 But as many as 1 in 8 juvenile offenders are under the age of 12. Of all the juvenile sex offenses, only about 7% are committed by females. When females do commit sex offenses, they are much more likely to victimize family members.