I have prosecuted child abuse and neglect cases for a little over twelve years now (on the family court side - think foster care, not jail). I've seen things that would make people's heads explode, including a case just a few weeks ago with a very similar fact pattern. I've read the accounts, watched the interviews, and seen it all play out far too many times.
Sandusky has six adopted kids. One of his adopted kids already made claims to have been s e xually abused by his father. Given what we know of Sandusky's behavior with The Second Mile, there's a strong likelihood all/most of those adopted kids were abused. For one of those kids to have subsequently abused other kids is the most predictable thing in the world. It is sad and tragic, but predictable. I don't want to tell you of the cases I've had where the 13 year old kid is abusing the 9 year old who is abusing the 5 year old because Dad has been abusing the 13 year old and started on the 9 year old (all while Mom averts her eyes and doesn't ask questions because she doesn't want to know.)
It is a sick, evil, fallen world we live in.