Be grateful Trojans have replaced dried sheep guts.
That's one of the things I learned from this history of safe sex, courtesy of TIME. It's written in conjunction with attempts to revive the popularity of the female condom, which you can read about here.
A second-generation female condom just won a Food and Drug Administration advisory panel's approval. The new version costs less and is supposedly, um, less slippery.
At it's progress from the ancient Egyptian spermicide: crocodile dung.