I was reading David Graebers Debt and had a thought: Sex work is inherently involuntary. Most prostitution as in selling your body for money or survival appeared together with the poor and rich divide and with people getting into debt and being forced into the profession. Prostitution was not a voluntary profession even in ancient Babylonian times. Babylonia actually had prostitutes next to sex positive temple workers that did it because sex for pleasure is divine, and not for the money (although the line between them blurred with time).