Lock them up, segregate them, or kill them. Don't commit violence that gives people room for revenge. That is just asking for trouble. You should think these things through rationally before you pronounce punishments. However, it's not that simple.
Stat rape is a touchy subject.
I think the legal age is 18, but it should be more like 16. But it should be more enforced. Kids may seem like they can have sex at 15 and younger, but physically, females may not be developed enough. Sure, I had sex when I was 12. But I HAD NO IDEA what I was doing.