It's a question that has probably come up in every single sex-ed class (we hope, at least) — yet it remains one that continues to perplex many of us today: Can you really get pregnant if you have sex during your period?The answer is yes, you can get pregnant on your period. But, thanks to the way your menstrual cycle works, it's pretty unlikely.When you ovulate — usually around the 14th day of an average 28-day cycle — an egg leaves your ovary through the fallopian tube. It can hang out there for up to 24 hours while it awaits a sperm for fertilisation. Sperm can live from three to five days (and, in rare cases, up to seven days) inside a female body.That means that, if you have sex on the last day of your period and then ovulate early, there could be a stretch of time in which both sperm and egg are alive inside you, and meet. Although that's possible, a lot of circumstances need to line up perfectly for that to actually happen.This scenario is most likely if you have a shorter-than-average cycle, for example 21 to 24 days, which means you tend to ovulate earlier, according to the American Pregnancy Association . This is yet another excellent reason why tracking your cycle can come in handy — whether you're trying to get pregnant or trying to avoid it.More than anything else, though, it's a reminder that if you're not trying to get pregnant, making use of birth control (condoms or another method) is your best bet.