Girl 1: I get so scared sometimes, because I’m afraid the condom will break and I won’t notice it.

Girl 2:  Don’t worry, just double-bag with two condoms; you’ll get better protection.  If one breaks, there’s a backup.

This was the conversation between two girls at my lunch table. But Girl 2’s advice will hardly do any good. Double-bagging condoms—putting one on over the other—can cause friction and increase the risk of condom breakage.

The double-bagging myth is one of many sexual health myths that teens hear and take as truth. In some cases, these myths are harmless, even funny. But in other cases, they’re downright dangerous. 

To set the record straight on sex myths, I compiled six of the most common ones and dispelled them with the help of Judith Steinhart, M.A., senior health educator at Alice!—the Health Education Program at Columbia University, in New York City.

Myth 1: Double-bagging a condom is more effective than using just one.

“I used to double-bag till I realized that it isn’t any safer than using just one condom,” says George, 17, of Plainwell, MI.

George is right. Even though it seems logical that two is better than one, double-bagging a condom is NOT more effective. In fact, the friction caused by condoms rubbing together can increase the chances of breakage. 

“One condom will work,” says Steinhart. “The most common reason condoms break is human error, specifically dryness, rather than the condom itself.  Instead of putting on another condom, use a lubricant—such as Astroglide—inside the condom, to make it a bit more comfortable for the guy, and outside the condom, to keep things wet,” she says.

(To learn all the steps to correct condom use, click here.)

Myth 2: Masturbation makes guys semen dry up.

 Not true. Masturbation will NOT make guys semen “dry up.” In the early stages of puberty, a guy’s testicles start constantly producing sperm. So, even the most “active” masturbator won’t exhaust his supply.

“Males are continually producing semen, and it will not dry up. If it seems to dry up, just wait a few hours and more will be produced,” says Steinhart.

Myth 3: Girls who are virgins can NEVER get pregnant.

Not true. While unlikely, a girl who hasn’t had vaginal-penile intercourse can get pregnant.

“If, for instance, a girl’s hymen—the membrane covering her vaginal opening—doesn’t completely cover the opening, and a guy ejaculates his semen right near her vagina, there’s a small chance that sperm can make it to the egg and fertilize it. The possibility of that occurring is very unlikely, but it could and probably has occurred,” says Steinhart.

To completely reduce the risk, a guy should ejaculate far away from a girl’s vaginal opening. And both partners should always use two forms of contraception during any type of intercourse—oral, vaginal, or anal. One form (like a latex condom) to protect against sexually transmitted diseases (STDs), and another (like the Pill) to prevent unplanned pregnancy.

Myth 4: If a girl has sex right before her period, she can’t get pregnant.

Not true.

“A girl can become pregnant during any point of her menstrual cycle,” says Steinhart.  “Her peak time for becoming pregnant is during ovulation, but it’s hard to figure out exactly when a female ovulates.  In addition, sperm stay alive in the vagina for a few days, so that has to be taken into consideration as well. There is no sure ’safe’ time.”

So, no matter what time of the month it is, you should use two forms of contraception during intercourse.

Myth 5: A girl can get pregnant from oral sex with a guy.

“This is completely illogical,” says Steinhart, “Whether you’re giving or getting oral sex, the sperm aren’t anywhere near the vaginal opening and the girl will not get pregnant.”

Yet this doesn’t mean that oral sex is risk-free. 

Many STDs are just as easily transmitted during oral sex as during vaginal or anal sex. So, exercise good judgment. Communicate with your partner about your sexual history and always use protection. To protect yourself during oral sex with a guy, use flavored latex condoms. For oral sex with a girl, use a Sheer Glyde Dam.

Myth 6: A girl can’t get pregnant if she has intercourse in the water.

“I remember someone telling me that water kills sperm,” says Ruth, 15, of Montclair, NJ.

Like Ruth, some teens hear that sex in the water is “safe.” This is NOT true. 

“If a guy ejaculates in a woman during intercourse, it doesn’t matter what their surroundings are. The semen is deep inside her vagina, making pregnancy a possibility as well as STDs, if no condom is used,” says Steinhart.

So, when it comes to sexual health, what’s the best way to separate myth from fact? Don’t rely on rumors—get accurate information from credible sources, or ask educated adults or peer educators your sexual health questions.