A lot of us were taught as kids that the hymen is a thin layer of skin mostly covering the vaginal opening that "pops" or "breaks" when it's first penetrated.
And that the tearing of your hymen is what caused a lot of women to bleed the first time they had sex, right?
And that if you didn't bleed during sex it was probably because you accidentally "popped" your hymen horse-riding.
Well, it turns out most of that is pretty wrong.
Very wrong, in fact. It is impossible to know if someone has been penetrated or not by looking at their hymen.
"The hymen does not 'break' the first time you have sex," Rose Olson, lead author of a review paper on "virginity testing" published in the journal Reproductive Health and a medical student at the University of Minnesota, tells BuzzFeed. "Looking at the hymen can't prove someone has had vaginal sex, or anything else about their sexual history. Everybody's hymen looks different. Even the most experienced doctors cannot distinguish a 'virgin' hymen from a 'non-virgin' hymen."