Maybe they are horny. Voluntary ****.
i think its cause it is an easy job for them early on in life and they also have the bodies that are attractive to men. another thing could be because they enjoy sex and raunchiness.
Some probably enjoy being exhibitionists and getting paid for it is a bonus.
Besides money there's actually so many other reasons for them to make the choice of getting into the adult movie industry. Plenty of them just really enjoy the work. The social class it get's them into is another reason for a lot of them. And when we're talking about the most successful performers of all there are even more reasons to name.
For the money, duh..
money and psych issues