The urban legend circulates every single year: If someone ejaculates into a pool, some unknowing swimmer (or, in some variations of the legend, multiple swimmers) could inadvertently become pregnant. In reality, sperm can only survive for a few minutes outside of the body. Even if someone ejaculated in a pool as you were in it, there’s simply no way that the sperm cells would know to navigate through chlorinated water into the interior of someone’s vagina.
But sometimes, this debunked urban legend gets twisted again. The idea that you can’t get pregnant from a swimming pool becomes the myth that you can’t get pregnant in a swimming pool. Unfortunately, that’s not true either.
Both myths seem to have a fundamental misunderstanding about how the female reproductive system works. If a person with a vagina goes swimming, their vagina doesn’t just fill up with water. The muscles of the pelvic floor and the walls of the vagina prevent this from happening. Similarly, when someone has sex in a pool, chlorinated water isn’t being pushed into the vagina. The insertion of a penis into a vagina might introduce some chlorinated water into the vaginal cavity, but not at any level that would kill sperm. If someone ejaculates directly into a vagina while in a pool, the semen will mostly remain in the vagina. Some might leak out –– the vagina isn’t airtight –– but most of it will remain inside. When the penis departs from the vagina, the pelvic floor will tighten and again keep the pool water from entering.
Once inside the moist, warm and cozy vagina, sperm can survive for several days. They love it there! If available, the sperm will travel to an ovulating egg via the fallopian tubes and fertilize it. It doesn’t matter where you have sex –– if sperm enters a vagina with an ovulating egg, there’s a chance for impregnation.
While it would be nice if pools were some kind of neutral zone where pregnancy couldn’t occur, that would probably only happen if the other laws of vaginal integrity weren’t in place. You know how when you’re doing dishes and you’re washing a tall glass, you have to shove your fist in there and all the water that’s in the glass violently gurgles out? That’s what pool sex would have to be like in order for pool sex to be incapable of leading to pregnancy. The vagina would have to be like a pipe with immovable walls. And imagine just swimming with such a vagina? It would just fill up with water. Would you even be able to swim? Wouldn’t you possibly drown, weighed down by the water in your vagina?
Personally, I think the risk of getting pregnant from sex in a pool is a fair trade for not experiencing that.