In Michael Crichton's Pirate Latitudes, a character with syphilis believes that having sex with a virgin will cure it. Is there a history of beliefs that virgins cure STDs and how would they not almost instantly realize that this was not true?
As a follow-up, Crichton also has a character with the same belief in The Great Train Robbery, which takes place 200 years after Pirate Latitudes; assuming this isn't just a trope of Crichton's, how long did this belief persist?