You implied that prostitution is not just lowly regarded in every religion/culture... re; "First, we might want to look at the issue of how many parents in any world culture -- whether it's post-Enlightenment Protestantism or pre-colonial Yorubaland -- talk to their daughters about how proud they would be if they were to choose prostitution as a career path." Which isn't entirely true. Sex for trade is considered normal part of many cultures throughout history, neither high nor lowly regarded.

Shame of sex might stem from the Victorian-era, just as shame of sex for trade. I doubt Caligula had shame throwing a few coins at a whore.