Summary: I. Did cultural evolution create sexual purity taboos to prevent the spread of STIs? A few weeks ago, I wrote a post assuming this was obviously true; after getting some pushback, so I want to look into it in more depth. STIs were a bigger problem in the past than most people think. Things got especially bad after the rise of syphilis: British studies find an urban syphilis rate of 8-10% from the 1700s to the early 1900s. At the time the condition was incurable,
