if you allow your children to see their parents naked... (with edit... THIS ISN'T ABOUT STRANGERS!!)
How do you explain that although its acceptable to see mommy and/or daddy naked, other people shouldn't expose themselves to them. Or are you alright with other adults flashing your children?
Sexual abuse can include fondling, genital exposure, intimate kissing, forced masturbation oral, penile or digital penetration of the mouth, vagina or anus. Child prostitution, pornography and cult (or "ritual") abuse are specific activities also included in the definition.1 Incest is sexual abuse where the offender is a family member.
Most children are abused by someone they know and trust, although boys are more likely than girls to be abused outside of the family.2,5 A study in three states found 96 percent of reported rape survivors under age 12 knew the attacker. Four percent of the offenders were strangers, 20 percent were fathers 16 percent were relatives and 50 percent were acquaintances or friends. Among women 18 or older, 12 percent were raped by a family member, 33 percent by a stranger and 55 percent by an acquaintance.24
Oh yeah, I almost forgot... *source*