6 Major Myths and Misconceptions About Sex, Debunked

Considering that a lot of our earliest sex education comes from eavesdropping on older siblings or watching HBO at unsupervised friends’ houses, it’s no surprise that there are tons of misconceptions on the topic. Let’s learn the truth about blue balls, broken hymens, and what even counts as “having sex,” as adapted from the below episode of Misconceptions on YouTube.

While sometimes it might feel uncomfortable or silly, it’s important to debunk misinformation about sex so we can collectively have a better understanding of sexual health, equality, and pleasure. And since sex education is often a little dated, try and do your own research instead of just assuming your 8th-grade science (or gym) teacher knew everything there was to know about sex. 

1. Misconception: Sex burns a lot of calories.
2. Misconception: There’s a strict definition of “having sex.”
3. Misconception: For people with vaginas, “losing your virginity” involves tearing your hymen. 
4. Misconception: “Blue balls” is a harmful medical condition. 
5. Misconception: You can’t get pregnant while on your period. 
6. Misconception: You can’t get an STI from oral sex. 

Misconception: Sex burns a lot of calories.

Why go on a run when you can just have sex, instead? Well, sadly, sex isn’t the miracle calorie burner you might think it is.

In one 2013 study, 21 heterosexual white couples from Montreal, mostly in their early twenties, tracked their energy expenditure in two situations: during sex, and during 30-minute exercise sessions of “moderate intensity” on the treadmill. 

Researchers found that during sex, the women burned an average of 3.1 calories per minute, while the men burned 4.2. On the treadmill, the women averaged 7.1 calories, and the men averaged 9.2. In other words, they burned twice as many calories doing a moderate treadmill workout as they did having sex.

Granted, it was a small study that looked at a very narrow demographic. The number of calories someone burns during sex depends on everything from age and body composition to the type of sex they’re having. But here’s what Dr. Debby Herbenick, a professor of sexual and reproductive health at the Indiana University School of Public Health, told Insider: “It would be incredibly difficult for people to change sex in such a substantial way that it would be equivalent to a workout.”

Now, there are plenty of ways to justify going all the way rather than going all the way to the gym. Sex boasts its own health benefits, from reducing stress to boosting your immune system. But if it’s the only exercise you ever get, you might want to rethink your strategy.

Misconception: There’s a strict definition of “having sex.”

It’s hard to talk about sex without knowing exactly what we’re talking about when we talk about sex. But it’s also hard to know exactly what we’re talking about when we talk about sex. Because sex doesn’t have a universal definition.

The Oxford English Dictionary describes it as “physical contact between individuals involving sexual stimulation,” among other meanings. You can’t get much vaguer than that—and studies show that people have pretty wide-ranging opinions about the specifics.

In early 2023, for example, market research company YouGov polled about 5800 adults in the UK on what counts as “having sex.” More than one-third of participants said that hand jobs and fingering count as “having sex,” and about 45 percent of participants said that oral sex counts, too. Those stats were several points higher among gay, lesbian, and bisexual respondents [PDF].

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Another survey in 2015 asked nearly 600 heterosexual college students to classify different sexual activities as “definitely sex,” “probably sex,” “probably not sex,” and “definitely not sex.” About one-fourth of them said that oral stimulation without orgasm was definitely sex; and 70 percent said anal intercourse without orgasm was also definitely sex. “Deep kissing” was deemed definitely not sex by 92.3 percent of participants—but 0.8 percent said it was definitely sex. 

Again, these are small surveys focusing on small demographics that don’t adequately account for important variables like gender diversity and cultural differences. But even just the fact that there’s a study whose response options include the phrases probably sex and probably not sex does help prove our point that the meaning of “having sex” is up for debate.

Misconception: For people with vaginas, “losing your virginity” involves tearing your hymen. 

Since we don’t agree on what counts as “having sex,” it makes sense that “losing your virginity” is a similarly ambiguous concept. Historically, in our very heteronormative, gender-binary-obsessed world, a woman “lost her virginity” when her hymen—the thin membrane covering the vaginal opening—broke during the first time she had penis-in-vagina sex (often referred to as “popping the cherry”). 

This definition of “losing your virginity” has issues beyond just being really limited in terms of who it can happen to and what kind of sex is involved. For one thing, it’s predicated on a misunderstanding of the hymen. Here’s how Planned Parenthood puts it: 

“Most of the time, hymens naturally have a hole big enough for period blood to come out and for you to use tampons comfortably. Some people are born with so little hymenal tissue that it seems like they don’t have a hymen at all. In rare cases, people have hymens that cover the entire vaginal opening, or the hole in their hymen is very small … Some people are born with hymens that are naturally open.”

Sure, a penis can stretch or tear the hymen. But so can other things, and not just tampons or fingers or sex toys. Horseback riding, tree climbing, bike riding, dancing, gymnastics, and basically any other lively exercise can have the same effect. It’s often a gradual process that you’re not really aware of, and you can’t tell if someone’s ever had vaginal sex based on the state of their hymen.

In short, virginity is just a social construct. If you want to consider yourself no longer a virgin after some deep kissing,go for it. 

Misconception: “Blue balls” is a harmful medical condition. 

Blue balls is a colorful phrase that Americans coined more than a century ago for what the Oxford English Dictionary describes as “testicular discomfort attributed to prolonged sexual arousal without ejaculation.” It possibly started out as a real medical condition—a 1906 medical journal speculates that it’s a corruption of bubo, which are swollen lymph nodes in the armpit or groin. As this journal says, though, when non-medical professionals think of swelling in the groin their minds go somewhere very different, to something that’s also apparently been called “lover’s nuts,” which is way less catchy, but still catchier than medical professionals’ preferred term: epididymal hypertension.

Basically, pressure builds when blood rushes to your genitals during arousal, and then releases during orgasm. If you don’t orgasm, though, it takes longer for your blood flow to slow back down—and the prolonged pressure can be uncomfortable or even a little painful. But it’s not dangerous to your health. 

As Cleveland Clinic urologist Petar Bajic explained, “There is no risk or harm to experiencing blue balls ... It isn’t going to cause any kind of damage or problem to the testicles or the reproductive tract. … [It] definitely should not be used as a means to coerce anybody into having sex.”

And even though it’s called “blue balls,” it doesn’t only affect people with balls. Arousal causes blood to rush to your genitals, no matter what genitals you have. For people with vulvas, that extended pressure without release is sometimes called “blue vulva.” 

Misconception: You can’t get pregnant while on your period. 

If you think it’s impossible for period sex to result in pregnancy, you might appreciate a light refresher on—or introduction to—the menstrual cycle. So here it is. 

Basically, once every cycle, one of the ovaries releases an egg in a process known as ovulation. 

The egg travels through the fallopian tubes, where it may or may not get fertilized, and then into the uterus. The uterus, meanwhile, prepares for a possible pregnancy by thickening the uterine lining. If the egg doesn’t get fertilized, that extra tissue sloughs off and gets shed along with some blood. That’s menstruation, or the menstrual period. 

The menstrual cycle lasts from the first day of one period to the first day of the next period. You’re most likely to get pregnant if you have unprotected vaginal intercourse during or up to a couple days before ovulation. But that doesn’t mean it’s impossible to get pregnant if you do it during your period. 

Sperm can survive in the reproductive tract for up to five days—so it could still be viable for fertilization by the time the next egg gets released. These chances are higher if you have sex toward the end of your period, and if your menstrual cycle is especially short. The average cycle lasts 28 days, but some are a whole week or so less than that.

And just because you have a really predictable period doesn’t guarantee that ovulation will happen at the exact same time every single cycle. If you don’t want to get pregnant, you or your partner should use some form of contraception beyond just paying attention to the date.

Misconception: You can’t get an STI from oral sex. 

Plenty of people who are really diligent about using condoms for vaginal or anal sex are the same people who have unprotected oral sex without much of a second thought. PSA: Many sexually transmitted infections—including chlamydia, gonorrhea, syphilis, herpes, and HPV—can get passed through oral sex, too.

It’s tough to pin down precisely how often oral transmission of each disease happens, though, and how those stats compare to transmission rates from other kinds of sexual activity. As the CDC explains, that’s partly because most people who do oral aren’t just doing oral. 

The other factor, as is so often the case with anything medical or even vaguely science-y, is that more research is needed. What has been researched pretty extensively is HIV: The risk of getting it from oral sex is probably “extremely low” compared to vaginal or anal sex, per the CDC. But they then caution how hard knowing the actual risk is. And even extremely low is still some risk.

The best way to prevent contracting an STI from oral sex is to use protection: either a condom or a dental dam, which is basically a thin sheet of latex or some other material that serves as a mouth-to-genitals barrier during oral sex. You can even DIY a dental dam by cutting down the side of a condom to make it a flat surface. Or, you and your partner could just both get tested for STIs before you go down on each other.