Nina Dølvik Brochmann: We grew up believing that the hymen is a proof of virginity. But it turns out, we were wrong. What we discovered is that the popular story we're told about female virginity is based on two anatomical myths. The truth has been known in medical communities for over 100 years, yet somehow these two myths continue to make life difficult for women around the world. Ellen Støkken Dahl: The first myth is about blood. It tells us that the hymen breaks and bleeds the first time a woman has vaginal sex. In other words, if there is no blood on the sheets afterwards, then the woman was simply not a virgin. The second myth is a logical consequence of the first. Since the hymen is thought to break and bleed, people also believe that it actually disappears or is in some way radically altered during a woman's first intercourse. If that were true, one would easily be able to determine if a woman is a virgin or not by examining her genitals, by doing a virginity check. NDB: So that's our two myths: virgins bleed, and hymens are lost forever. Now, this may sound like a minor issue to you. Why should you care about an obscure little skin fold on the female body? But the truth is, this is about so much more than an anatomical misunderstanding. The myths about the hymen have lived on for centuries because they have cultural significance. They have been used as a powerful tool in the effort to control women's sexuality in about every culture, religion and historical decade. Women are still mistrusted, shamed, harmed and, in the worst cases, subjected to honor killings if they don't bleed on their wedding night. Other women are forced through degrading virginity checks, simply to obtain a job, to save their reputation or to get married. ESD: Like in Indonesia, where women are systematically examined to enter military service. After the Egyptian uprisings in 2011, a group of female protesters were forced to undergo virginity checks by their military. In Oslo, doctors are examining the hymens of young girls to reassure parents that their children are not ruined. And sadly, the list goes on. Women are so afraid not to live up to the myths about the hymen that they choose to use different virginity quick fixes to assure a bleeding. That could be plastic surgery, known as "revirgination," it could be vials of blood poured on the sheets after sex or fake hymens bought online, complete with theater blood and a promise to "kiss your deep, dark secret goodbye." NDB: By telling girls that no deed can be kept secret, that their bodies will reveal them no matter what, we have endowed them with fear. Girls are afraid of ruining themselves, either through sport, play, tampon use or a sexual activity. We have curtailed their opportunities and their freedoms. It's time we put an end to the virginity fraud. It's time we break the myths about the hymen once and for all. ESD: We are medical students, sexual health workers and the authors of "The Wonder Down Under." (Laughter) That's a popular science book about the female genitals. And in our experience, people seem to believe that the hymen is some kind of a seal covering the vaginal opening. In Norwegian, it is even called "the virgin membrane." And with this, we picture something fragile, something easily destructible, something you can rip through, perhaps like a sheet of plastic wrapping. You may have wondered why we brought a hula hoop onstage today. We'll show you. (Laughter) Now, it is very hard to hide that something has happened to this hoop, right? It is different before and after I punched it. The seal is broken, and unless we change the plastic, it won't get back to its intact state. So if we wanted to do a virginity check on this hoop right here, right now, that would be very easy. It's easy to say that this hoop is not a virgin anymore. (Laughter) NDB: But the hymen is nothing like a piece of plastic you can wrap around your food, or a seal. In fact ... it's more like this -- a scrunchie or a rubber band. The hymen is a rim of tissue at the outer opening of the vagina. And usually, it has a doughnut or a half-moon shape with a large, central hole. But this varies a lot, and sometimes hymens can have fringes, it can have several holes, or it can consist of lobes. In other words, hymens naturally vary a lot in looks, and that is what makes it so hard to do a virginity check. ESD: Now that we know a bit more about the hymen's anatomy, it's time to get back to our two myths: virgins bleed, hymens are lost forever. But the hymen doesn't have to break at all. The hymen is like a scrunchie in function as well as in looks. And you can stretch a scrunchie, right? (Laughter) You can stretch a hymen, too. In fact, it's very elastic. And for a lot of women, the hymen will be elastic enough to handle a vaginal intercourse without sustaining any damage. For other women, the hymen may tear a bit to make room for the penis, but that won't make it disappear. But it may look a bit different from before. It naturally follows that you can't examine the hymen to check for virginity status. This was noted over 100 years ago in 1906 by the Norwegian doctor Marie Jeancet. She examined a middle-aged sex worker and concluded that her genitalia were reminiscent of a teenage virgin. But that makes sense, right? Because if her hymen was never damaged during sex, then what were we expecting to see? ESD: Since hymens come in every shape and form, it is difficult to know if a dent or a fold in it is there because of previous damage or if it's just a normal anatomical variant. The absurdity of virgin testing is illustrated in a study done on 36 pregnant teenagers. When doctors examined their hymens, they could only find clear signs of penetration in two out of the 36 girls. So unless you believe in 34 cases of virgin births -- (Laughter) we must all agree that also our second myth has taken a vital blow. You simply cannot look a woman between her legs and read her sexual story. NDB: Like most myths, the myths about the hymen are untrue. There is no virgin seal that magically disappears after sex, and half of virgins can easily have sex without bleeding. We wish we could say that by removing these myths, everything would be OK, that shame, harm and honor killings would all just disappear. But of course, it's not that simple. Sexual oppression of women comes from something much deeper than a simple anatomical misunderstanding about the properties of the hymen. It's a question of cultural and religious control of women's sexuality. And that is much harder to change. But we must try. ESD: As medical professionals, this is our contribution. We want every girl, parent and [future] husband to know what the hymen is and how it works. We want them to know that the hymen can't be used as a proof of virginity. And that way, we can remove one of the most powerful tools used to control young women today. After telling you this, you may wonder what the alternative is, for if we cannot use the hymen as a proof of virginity for women, then what should we use? We opt for using nothing. (Cheering) If you -- (Applause) If you really want to know if a woman is a virgin or not, ask her. (Laughter) But how she answers that question is her choice. Thank you. (Applause)