The hymen or the “virginal membrane,” was such a delicate thing. You could damage it if you got too curious and try to find out what was in your vagina by touching it. Or if you got too close with men, or if you jumped down from a wall. You would lose ‘the blood’, and then you were doomed. No one would marry you, and you would have only one option: to become a prostitute.
Interesting cause and effects here. If that were the case for men, there would be roughly 3.5 billion male hookers.