The easiest way to prove this is that there arn't many male prostitutes compared to female ones. There just isn't the demand for them.
What puzzles me is why this should be such a big deal? Whenever someone mentions that men, on average, have higher sex drives than women, it causes outrage.
But why?
Surely it's a good thing that females have lower sex drives. It certainly isn't something to get angry about.
Men and women are biologically different. So why wouldn't this shape behaviour?