Most dudes don't exactly have a reputation for knowing their way around a vagina—and they won't ask for directions! Right, ladies? And then their lack of communication about sex slowly tears their marriages apart until all that's left is two near-strangers sleeping in separate beds in the same house! LOL! 

But seriously, a lot of dudes—and even a lot of women—don't fully understand what's going on with the female reproductive system. And this is especially true for the hymen, which is not (despite what you've been told) some little flesh circle that gets torn away when you have sex for the first time (or just stretch too much). In fact, 52% of sexually active teenage girls have their hymens intact, which is pretty mindblowing if you think about how pointless that makes "checking" a woman's hymen for anything. To learn more about that and other HymenFacts, check out this video from Adam Ruins Everything, where costar Emily Axford pops Adam's smugness bubble and explains how the hymen really works:

Sources: College Humor