There’s a very interesting article in The Times about the ridiculous American invention of silver chastity rings. From the article:
He discovered that while 7 per cent of nonpledging teenagers had contracted an STD, 4.6 per cent of what he called “consistent” pledging teenagers had also managed it, presumably by agreeing to oral or anal sex in the belief this maintained purity. Interviews showed that while only 2 per cent of nonpledging teenagers had consented to oral sex or sodomy, 13 per cent of those in the “consistent” pledging category had.