All adult sex work should be legal across the board. Anyone, of legal age, should be allowed to not only sell their services but they should be able to pay taxes and be allowed to unionize and collect benefits from any organization they work for (brothels).
A lot of the people in this world who are messed up in the head just need to get laid, and those doing to dirty work should be celebrated and rewarded for their efforts. I genuinely think this would make the world a better place.