Originally Posted by s_k

I think it's the same with necrophiles and pyromaniacs and murderers. Or probably even the same as people who enjoy sex in public, SM or Sex with animals.
Some twisted 'error' in their brains. Sometimes born that way, sometimes triggered by certain experiences in the past.

Nevertheless, I think in a lot of people's minds there's quite a lot going on that really definitely has to remain a fantasy. I think in a lot of cases it has more to do with the question whether a person can behave himself, than the actual sexual preference.

This, of course, is speculation.