Size matters. You can’t get a sexually transmitted infection if you use a condom. Men have higher sex drives than women. Have you heard these common sexual assertions tossed about? Guess how many are actually true?

It’s harmful to believe generalizations, stereotypes and hearsay about sex and sexual health, and researchers are learning new information about it every single day. Remember there are so many different kinds of sexual experiences, preferences and desires, as well as human biology to consider when it comes to weighing myth versus fact.

Don’t worry if you aren’t yet an expert on orgasms and intercourse. Below, experts clear up the most common sex-related myths they hear perpetuated:

Myth: You can get pregnant on your period.

It’s rare to get pregnant on your period ”• but that being said, there’s a caveat, according to Dr. Christine Greves, an OB-GYN at Orlando Health Winnie Palmer Hospital for Women & Babies.

“If the bleeding you’re having is because of a true period, meaning you ovulated 14 days ago, then there is no egg available to fertilize at that time,” she explained. “The problem with saying that you ‘cannot get pregnant on your period’ as a general statement? Sometimes women have bleeding not associated with a true period, and they may think they are getting a period, but that’s not actually the cause of bleeding.”

Infections, fibroids and hormone shifts can also cause you to spot or bleed at odd times in your menstrual cycle. It’s best to be on the safe side and use protection no matter what if you’re not trying to get pregnant.

Myth: You can’t get an STI if you use a condom.

You’ve likely heard that you should always use a condom to protect against sexually transmitted infections ”• and yes, that is true. But you should still exercise caution: While condoms are highly effective in preventing STIs passed through bodily fluids, like gonorrhoea or HIV, condoms are less effective in preventing infections contracted through skin-to-skin contact, like HPV or herpes, according to the American Sexual Health Association.

That being said, safe sex is still very possible with protection and communication. Condoms do offer some protection from skin-contact conditions and should be used to prevent an array of STIs and unintended pregnancy. Also, although you’ve been hearing this suggestion repeated since sex ed, it still holds: Talk to your partner about condom use and STIs — or get tested before sex if that route makes you feel comfortable and safest. 

Myth: It’s OK to fake an orgasm.

Faking orgasms is never a good idea, even if you’re trying to kindly preserve someone’s ego, said Sarah Hunter Murray, a sex researcher and relationship therapist.

“Orgasms and other signs that we are experiencing pleasure during sexual activity, like words of affirmation or moaning, are cues to our partner that they are doing something we like,” she said. “If sex isn’t feeling so good, but we pretend that we are enjoying ourselves, our partner is understandably going to keep doing the stuff we’re not that into.”

What to do instead? Be vocal. “Positively encourage behaviours that are actually satisfying ”• or talk honestly about what’s not working as well,” Murray added.

Myth: You can’t get pregnant unless a man ejaculates during intercourse.

There are lots of urban legends out there about how exactly you can and cannot get pregnant when it comes to male-female sex, but let’s clear those up.

“One of the most widely believed myths is you won’t get pregnant if you pull out in time, but that isn’t the case,” said Dr. Mache Seibel, a health education expert. “Many times, the precum or pre-ejaculation spurts out ahead of the larger volume of semen,” but still contains some sperm, Seibel explained. It’s why the pull-out method ”• or withdrawing before ejaculation ”• sometimes fails.

Also, anytime sperm enters the vagina, “pregnancy is possible,” Seibel added, though “not nearly as likely” in the cases of indirect delivery, like say on a finger or vibrator. Concerned? Don’t rely on pulling out and be safe with birth control.

Myth: Women usually orgasm from penetration.

A 2015 study published in the Journal of Sex shows that just 18 percent of women report that intercourse alone is enough to orgasm.

“These findings show that the majority of women cannot orgasm through penetration,” said Sunny Rodgers, a clinical sexologist and certified sex coach. “Most women need specific clitoral stimulation to bring them to actual orgasm.”

You might like stimulation on its own or with intercourse. Murray suggested “woman on top” or “using an extra hand” during penetration to make sure both parties are getting what they need to get off.

Myth: You’ll “just know” when you orgasm.

Those who claim climaxes are unmistakable aren’t exactly correct. “I’ve met many women who do not know if they’ve actually had an orgasm or not,” Rodgers said. “This is common.”

Why the myth? Rodgers said women fake a lot of orgasms, whether to preserve their partner’s ego or get sex over with faster. Women have different kinds of orgasms, as well ”• clitoral, vaginal, g-spot ”• that men simply don’t have, so it can be hard to know exactly what you’re feeling.

“They also believe that sex will always bring them to orgasm, which just isn’t true,” Rodgers said.

There are ways that a person can determine if what they’re experiencing is indeed an orgasm. Expect your heart rate and blood pressure to increase, your skin to flush and your muscles to tense while stimulated. “This is followed by the release of tension and a feeling of deep relaxation,” Rodgers explained. Yes, it should feel amazing.

Myth: Size is everything.

“That old saying is true: It’s not the size of your boat, it’s the motion of your ocean,” Rodgers said. Penises are “a varied bunch,” she explained, with size and shape are unique to each guy.

“What is perfect for one person can be too large or too small for another,” Rodgers said. “On top of that, there are so many techniques, positions and enhancement products available now that size is not the only relevant factor for sexual satisfaction.” Explore, experiment, enjoy ”• and forget this myth.

Myth: Men want more sex than women.

This stereotype might be damaging sex lives everywhere. According to a series of 2016 studies, men typically underestimate how often their long-term girlfriends or wives want sex. A survey conducted that same year also revealed 71 percent of female respondents said they’d like to have more sex in the coming year.

“The brain is a more powerful sexual organ than genitalia, because it’s where sex drive stems from,” Rodgers said. “It may seem like men have a higher sex drive just because men do tend to think about sex more often ... but there is no single measurement of sex drive, so it is an interesting assumption.” And not always true. Don’t assume!

Myth: Orgasm is the goal of sex.

Everybody loves to orgasm, but make sure you’re aware of each other’s sex goals. “Wanting to experience pleasure from sex is a good thing,” Murray said. “But while orgasms are often perceived as the main event or the star of the show, focusing too much on orgasms can set couples up for frustrating sex.”

You know what they say: It’s about the journey, not the destination. Focusing on getting to orgasm can cause you to miss other positive elements of your sexual experience like “sensations and pleasures along the way, making out, gentle touches and caresses and feeling close to our partner,” Murray said. (And bonus: All of those things can boost your mood, according to research.)

Not to mention, sometimes an orgasm just doesn’t happen for variety of reasons, like stress or alcohol, so try to enjoy your intimate experience regardless.