.....the rapists why they rape? That just might give a hint as to the motivation behind rape. I have to admit to NEVER having heard a rapist say that they raped to get someone pregnant without the liability of child support payments!!! Men can do that without raping and they do it every minute of every day (don't mean to sound anti-male, but it is a fact).
I'll need to try to dig out some info on this. I'm sure I've seen a study on serial rapists who, when asked why they did it, said it was all to do with power and humiliation of women. Some hated women, some were "getting their own back", none said that it was to father a child.
We should leave "date rape" out of this as this can be construed as a guy too keen, too thick or both, to understand that "No" means "No". A sort of crossing of wires.