Re: US-centric
In the US, however, it has become The Most Evil Word Ever™, presumably because of their Puritan history.
I don't think the Puritans have much to do with it. They were actually pretty liberal when it came to talking about the naughty bits, and for that matter about using them. Some studies of their records suggest a majority of women were either pregnant or had children by the time they were married. And it was customary, at least in some communities, that if an eligible bachelor stayed overnight with a family that included an eligible daughter, the two would sleep together; we have various documents substantiating that.
What did happen in the US, but in the eighteenth and nineteenth centuries – well after the Puritans had become no more than a relatively minor (if wildly overrated) chapter in US history – was a long-lasting panic over any mention of female anatomy. Bryson (yeah, I know, but he cites reliable sources in this case) discusses it at some length in his book on US English. It was so bad that serious medical conditions often went untreated because women couldn't describe their symptoms to doctors.
The reasons for this are unclear, but they probably have more to do with social climbing and attempts to delineate class structures, which historically have been nebulous in the US, than with leftover Puritanism.
Things are improving, though. Why, in the states covered by the 10th circuit, women can go topless in public now. They pretty much never do, but they can, at least anywhere men can. (Businesses, for example, can require shirts for everyone.) The day may yet come when we're not stricken with horror at the prospect of our own bodies.