Whether it's the constant fretting over Miley Cyrus' influence on school girls or the growing (and troubling) tradition of Purity Balls, it's clear that society has a fascination with young women's sexuality — especially when it comes to controlling it. But what are we actually teaching today's girls about sex?

Fueled by outdated ideals of gender roles and the sense that female sexuality is somehow shameful, there seem to be certain pernicious myths about girls and sex that just won't die. That sex education in America has gaping holes in its curriculum hasn't helped much, either; in a recent Centers for Disease Control (CDC) report just 6 out of 10 girls said that their schools' sex ed program included information on how to say no to sex. This lack of personal agency was reflected in a forthcoming study by sociologist Heather Hlavka at Marquette University as well, which found that many young girls think of sex simply as something that is "done to them."

Knowledge is power, and we can promote a healthier relationship with sex by encouraging a more open dialogue, teaching girls to feel comfortable with their sexuality and, most importantly, emphasizing that their bodies are theirs and theirs alone. But first, we're going to need to stop perpetuating the following 17 myths about female sexuality.

1. Virginity exists.

Therese Shechter's 2013 documentary How To Lose Your Virginity asks a seemingly simple question: What is a virgin? The answer is actually pretty complicated. The common idea of virginity is focused on a heteronormative, male-centric definition of intercourse — that is, penis-in-vagina penetration. But this definition ignores LGBTQ couples, oral and anal sex, instances where it "didn't go all the way in," rape and emotional intimacy.

The cultural obsession with virginity is more about keeping girls pure than anything else, and because the term begins to crumble upon close inspection, it doesn't have to carry such weight. There's no clear universal concept of virginity, and people should be able to define meaningful markers of intimacy for themselves.

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2. Hymens are a sign of virginity.

Given that the entire notion of virginity is dubious at best, it's not all that surprising that there is actually no medical way to tell if someone is a virgin or not. This includes a broken hymen. Hymens usually become worn down throughout adolescence, and can be torn by everything from jumping on a trampoline, to horseback riding, to simply playing sports. Some women aren't born with one at all.

Despite the fact that more than half of women don't bleed the first time they have penetrative sex, blood on the sheets has remained a signifier of losing one's virginity throughout history. The persistence of this myth surrounding a basically irrelevant anatomical feature has even spawned a market for artificial hymens and reconstructive surgery to "restore" virginity. More disturbingly, girls around the world are often subject to degrading, invasive virginity "tests" to ensure their purity.

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3. All women are born with vaginas.

Some items on this list focus on the anatomy of those assigned female at birth in an effort to illuminate issues that many girls don't get to talk about enough, but the purpose is never to be exclusionary. Gender identity is different from biological sex, and trans women are women, period.

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4. The first time is going to hurt — a lot.

Much of the pain young women are taught to expect during their first sexual experience actually comes from increased muscle tension due to nervousness. Blood usually comes from vaginal tissue tearing due to lack of lubrication and, ahem, inexperienced love making — not the hymen breaking. It's a self-fulfilling prophecy, really; maybe if we stop telling girls to be terrified of the excruciating pain of their first time, things would be a little more comfortable for everyone.

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5. If someone buys you something, you owe him or her sex.

It doesn't matter if it's a drink or a diamond necklace: You never "owe" someone sex. Ever.

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6. Too much sex will stretch you out.

Nothing like the old "hot dog down a hallway" analogy to scare young women away from safe, consensual promiscuity. The truth is, women differ in size just like men do. The vagina is like a rubber band, and unless you're regularly getting down with fire hose, you should be fine.

Similarly, having a baby will not "ruin" your vagina. Many women report feeling different down there after childbirth (the post-baby healing process depends on a variety of factors like age, the size of the baby and your commitment to Kegels), but we should really be teaching girls to accept their differences as normal and natural — not as new-found flaws.

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7. Women don't think about sex very much.

Many sexologists have arrived at the same conclusion: Women want sex just as much as men. This isn't some new trend, either; science is just learning to ask the right questions about female desire.

So why does this myth of the undersexed female persist? It certainly doesn't help that women often are taught that thinking about sex is boyish or juvenile. Entertainment media also frequently likes to portray women as the more responsible party in a relationship (think: nagging wife, childish husband).

The flip side of this thinking is the idea that "real" men should always have a voracious sexual appetite. But the saying "men think about sex every seven seconds" is just not true. Society's focus on young men's libido has created a sort of caricature of male sexuality, one that treats an occasional lack of desire or displays of emotion as not being masculine enough. And that's not fair to them, either.

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8. Women don’t like casual sex.

Not only do women want sex, but as journalist Daniel Bergner points out in What Do Women Want? Adventures in the Science of Female Desire, their desire is "not, for the most part, sparked or sustained by emotional intimacy and safety." This means that, contrary to popular belief, women can most definitely have sex without getting emotionally attached. Studies of sexual desire have actually shown that plenty of ladies want casual sex more than the average guy, and many guys want it less than the average lady.

Much of this desire appears to be socially conditioned, anyway: Gendered differences in desire have been shown to diminish over time with more progressive generations, in countries with more equitable distributions of power and when the perceived stigma of being slut-shamed is controlled for in female subjects.

Moral of the story? It's a personal preference, and blanket generalizations aren't helping anyone.

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9. Boys buy the condoms.

You don't need to depend on anyone else for your protection. Girls can be prepared, too.

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10. "Frigid" wives make cheating husbands.

The myth of the frigid wife plays off outdated notions of women who are too uninterested in sex to keep their men satisfied. But instead of lazily blaming infidelity on gender stereotypes, let's encourage a sense of personal responsibility. Besides, men deserve more than to be treated like animals who can't control themselves.

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11. You have to wax.

Despite ads that try to convince women life can only be fully enjoyed stubble-free, you do not have an obligation to do anything to your body that you don't want to do. After all, hair removal is still an industry, designed like every other to exploit people's insecurities to make the most money possible.

It's working, too: Hair removal is a $2.1 billion industry in the U.S., and over the course of a lifetime the average woman will spend an estimated $10,000 on shaving products. You should do what works for you, whether or not that means buying in.

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12. You can't have sex on your period.

If it grosses you out, no pressure. (Seriously though, is period blood really that much grosser than regular sexy-time fluids?) But such an act is both physically possible and safe. In fact, sex during your period can improve menstrual cramps, and some women even report having a shorter period overall when they get busy during that time of the month. Be warned, however: It is still possible to get pregnant or spread an STI while on your period, so don't forgo the condom.

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13. Sex is supposed to hurt sometimes.

Sex is not supposed to hurt, but for many women, it does. If your muscles aren't ready, things can get painful. It can take 20 minutes of foreplay for a woman's vaginal muscles to relax enough to be truly ready for penetrative sex.

For some women, however, foreplay isn't the issue at all. Conditions like vaginismus and vulvodynia are very real, albeit unfortunately not very well known. The result is that many women suffering from these conditions don't realize that there is help available. If sex hurts, it's worth finding a specialist who can talk you through your options.

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14. Once you start having sex, you're not allowed to say "stop."

You can change your mind at any time during sex, and your partner must respect that. It doesn't matter if blue balls are real or not. Know that your voice must be heard.

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15. Women don’t watch porn.

The hatred many women feel towards porn is understandable, given that so much of it promotes unrealistic or downright unhealthy attitudes about female sexuality. The problem is, as the Kinsey Institute's Debby Herbenick points out, "Most mainstream porn is made by men with other men in mind."

This doesn't mean that many women don't enjoy porn, nor that there's not a market for more female-friendly fare. Researchers have shown that men and women respond comparably to sexually explicit material, and that the increase in women's brainwave activity when looking at erotic images is just as strong as the increase in men's.

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16. Sexual harassment is normal.

A disturbing new study concluded that many young women consider sexual harassment and violence to be part of everyday life. Girls shouldn't have to think of this treatment as expected. Sexual violations of any kind are unacceptable, and the dismissive "boys being boys" defense is both ridiculous and damaging to all genders. Sorry, personal bodily autonomy is not up for debate.

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17. Everybody's doing it.

The average American loses his or her virginity, for lack of a better term, at age 17. Plenty of people don't start having sex until later (or earlier) in life, and that's okay, too. Some people don't have much of an interest in sex at all. Being sex positive isn't about encouraging everyone to have tons of sex all the time; it's about understanding that sex should be safe, shame-free and above all, based on informed, personal choices.

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