This one is pretty easily debunked. Tampons and menstrual cups are designed to be fully absorbent and make swimming and other activities blood-free, hence all those slightly confusing ads about women in white swimming costumes frolicking about. Even Olympic swimmers like Katie Ledecky are open about the fact that they can need tampons while competing. But have you ever seen any blood in an Olympic pool? Nope.

This is based on a fundamental misunderstanding of the hymen, the stretch of tissue inside the vagina that's traditionally associated with "tearing" when you first have intercourse. However, period blood needs to come through somehow, and hymens will already have holes by the time you have your first period. Totally impermeable hymens with no holes whatsoever are extremely rare, and people who have these will not experience any flow at all when they begin to menstruate.

Furthermore, virginity is a completely outdated concept, and having sex for the first time — no matter what that looks like — is a completely personal experience that definitely doesn't need a label.

This goes back to ancestral beliefs about the shame and taboo associated with menstruating. No, people cannot smell the scent of your blood on your pad. Dogs, with their strong sense of smell, can tell if you're menstruating, but not through detecting the blood inside your body. They tend to sniff out crotches more during their periods, says science, because of hormonal changes in the glands in the groin area during menstruation. People do not possess the same sense of smell as dogs, so no, you aren't "smelly" if you're on your period.

This is a belief found in many cultures worldwide, and can mean that people on their periods are forbidden from preparing food, pickling or preserving fruit and vegetables, or going near perishable items in case they "spoil" them. People view period blood as a kind of bodily waste in the same category as feces, but that's actually not correct. Period discharge is a mix of blood and the tissue lining of the uterus, and no, none of it is toxic to the outside environment or in any way dangerous or "unclean." And your body itself definitely doesn't become toxic while you happen to be on your period.

This is one of the superstitions around periods that, according to period tracker app Clue's research, is particular to the United States and the UK. The myth appears to go one of two ways: either people worry that their blood will "flood" the bath, or that the water will "stop" the period altogether. Neither are true. Dr. Jessica Shepherd, OBGYN explained to Elite Daily, "Due to counter-pressure of the water, the menstrual flow is stopped from exiting your body and does not enter the water. Additionally, if you are floating or swimming, gravity isn't strong enough to pull it out when you're standing in the water." In fact, a hot bath is a tried and true method for keeping cramps at bay, so don't be afraid of a good soak.

You can understand why this myth might take hold, but science has indicated that there's not much truth in it. Let's take the shark myth first. For one, as we've noted, menstrual blood doesn't usually leak into water. For another, great white sharks can only detect a tiny amount of blood in around 100 liters of water, a far smaller amount than any ocean around, and humans don't produce enough menstrual blood to interest them. They're going after wounded seals, not small bits of uterine tissue.

When it comes to bears, you can go camping during your time of the month without fear: a study in 2012 thoroughly debunked the idea that bears can detect menstruation. The only possible exception was polar bears, but the data on them was so small, and contact with humans so limited in real life, that it's difficult to draw firm conclusions. Besides, "steer well clear of bears" holds as good advice no matter where you are in your cycle.

It is entirely possible to get pregnant on your period, so don't let anybody tell you that you can neglect protection and contraception during that phase of your cycle. The important issue here is that sperm is tenacious; it can last inside the body for up to five days, meaning that if you have sex at the very end of a period and ovulate quickly afterwards, it's completely possible to get pregnant. It's not common, but it does happen.

Your mom may have been the source of a lot of intelligent advice about menstruation and your period, but if she breaks out any of these myths — or if any of your own friends bring them up — you know better. Shut that down.