I'm actually not familiar with the piece of the report you're speaking of, but I could make a very educated guess. Often it's one way that women are allowed to exit. If I've been recruited in when I'm 14, I've serviced thousands and thousands of men. My pimp has threatened to kill me and says, “You know what? One way you can get out of this and stop having to do this is that you can become a trafficker. You recruit me two girls, and you're out. You become an enforcer.” For women, often the only route they're given out is to become a trafficker, so it's what I would attribute it to.
On April 30th, 2009. See this statement in context.