Well, there is a combination. One of the problems is that the mothers of many of these girls are prostitutes. There is no real support at home to prevent this sort of activity. There are other abusive situations as well. Very often, when you're dealing with girls as opposed to adults, they're typically coming from a very bad home situation.
Of course, there are commercial networks making money out of this, but they find a willing market. Part of the problem, of course, is that when you're dealing with girls or young people, they don't necessarily know what they are getting into, and they are easily misled, hoodwinked, or painted a rosy picture. There is a lot of misinformation out there, which of course the exploiters take advantage of, and a lot of the prevention is simply getting the right information out.