About 75% of reported abusers are male, but there have been studies indicating that in terms of actual abuse it's about 50/50. It's not always a matter of gratification. With female sexual abusers, it's often for control or humiliation. Kids who live through something like that often feel like their the only person in the world who's ever experienced anything like it. We don't see crazy abusive mothers or aunts or sisters in PSAs or after school specials or movies, unless the villain's life is shown in flashbacks, to explain why he's crazy and evil. Poor fucking kids. It's actually the most psychologically damaging kind of abuse.