I heard that if you have sex during your period, you can’t get pregnant. Is that true? And isn’t doing that kind of… gross?

Good question(s)! It IS possible to get pregnant from period sex, although it is less likely than other times of the month.

A quick overview of what’s up down there throughout the month: the typical teen’s menstrual cycle can last anywhere from 28 to 42 days. Ovulation (when your ovaries release an egg into the fallopian tubes) always happens 14 days before the start of your period. This means that you can count backwards and know when you ovulated during your last cycle.

However, it’s a lot harder to predict the future!

Conception is possible for up to five days before ovulation, and the timing of ovulation can vary from person to person and from month to month. Also, sperm are super hardy—they can live in the body for up to five days after you have sex. All this adds up to a serious gamble if you’re not ready to get pregnant.

Sound like a lot of complicated math? Trade that calculator for a condom. Tracking your cycle—in your planner or on an app like Clue—can be an awesome way to learn more about your body. Unfortunately, cycle-tracking is just not a reliable birth control method, especially for young people, whose cycles are often irregular. Talk to your medical provider about finding a trusted method that’s right for you!

As for the other part of your question…

Is Shark Week sex “gross”?

Periods are just another week in the month for half the population—there’s nothing gross about them. As for period sex, it totally depends on how you (and your partner) feel! It’s completely ok if you don’t feel comfortable having sex when you’re on your period. If you feel fine with it though, the red tide certainly doesn’t have to be a red flag. Throw down a towel or hop in the shower so you don’t stain your sheets, and go for it. Some people even say that having an orgasm (solo or with a partner) releases endorphins that can help relieve cramps!

You should be aware that it is slightly easier to transmit sexually transmitted infections (STIs) when you’re on your period. However, so long as you use a condom, there’s no medical reason not to have sex. So if you’re both in the mood to surf the crimson wave, strap on that life jacket and go ahead!

A version of this post was originally published in November, 2016.