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How sperm got all the credit in the fertilization story

The school system probably failed you. Here’s how fertilization really happens.

Edward Vega joined the Vox video team as a video producer in 2021. His coverage focuses on all things cinema, from the intricacies of film history to the nuts and bolts of filmmaking.

The fertilization story most of us know is skewed. In the textbooks we read in middle school and high school, it’s presented as a sort of fairytale: The strong sperm go on a journey where they have to defeat and overcome obstacles to reach the egg. Meanwhile, the egg just sits around waiting to be fertilized.

The story inherently carries a lot of gender bias, and what’s worse is that it’s not entirely true. The sperm can’t make the journey on its own, and the real story of fertilization involves two reproductive systems working together. While sperm have tails that seem like they’re meant for swimming, they can’t propel themselves all the way to the egg — they need the female reproductive tract to help move them forward. And the egg doesn’t just wait around for the sperm to reach it; it has an active role in selecting which sperm will be the best one to fertilize it.

So why has the fertilization story been skewed in this gender-biased way? We dig into a study of textbooks from middle school to medical school to find out.

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