Sex (Re)Education: The Egg & The Sperm
How does fertilization occur? You undoubtedly have developed some sort of knowledge about this process over the years. Your science textbook details this by telling an epic story of sorts: Man ejaculates into woman, and sperm set off in a race to the finish! Thousands of tiny sperm swim against the current, up a woman’s vagina and at “tail-thrashing speed” towards a woman’s fallopian tube where a sitting egg awaits to be penetrated! Once the sperm reach the fallopian tube, and the awaiting egg, there is a “frantic battle to the finish,” all trying to reach the egg’s nucleus, where the sperm will then release its own genetic contribution. And may the best sperm win!” And then? The strongest, most successful sperm succeeds in penetrating the egg, succeeding in fertilizing it, and majestically completing the process of fertilization, and completing conception.
I’m pulling these descriptions directly from educational websites meant to inform you of what happens when pregnancy occurs. Science textbooks often (though not always) reproduce similar narratives in order to teach students about the process of fertilization(1). The imagery of sperm being active, strong, speedy, and adept is repeated over and over again in science magazines and in popular culture. One article in a national science magazine went to comical extremes, describing sperm as “a formidable .00024-inch weapon, tipped with a chemical warhead”. Yeah…alright. Calm down.
The problem with this story is that…it’s just all wrong.
Sperm are actually quite poorly adept at fertilizing eggs. It’s actually a wonder that anyone is ever to get pregnant, frankly, when you consider how downright abysmal sperm are at fertilization. Sperm, in fact, do not swim, they do not battle, they do not have brains. The movement that occurs that gets them from vagina to fallopian tube can be described instead as random thrashing that occurs in every single direction– not just up, the vagina, and not just towards the fallopian tubes where an egg “awaits”. They get to an egg by absolute chance alone, in fact.
The egg too, is mischaracterized in these text book stories. Studies have shown that sperm are actually also not well adept to penetrate the egg, either. Apparently, sperm are more prone to miss the egg entirely once they get near it, than to penetrate it because their tails propel their heads about in every which way. Eggs actually holds the sperm’s head in place on the zona so that it doesn’t escape, and on top of that breaks down the walls of the zona at a precise time so that the sperm is able to get through it. (2)
But why does any of this matter? This type of language, when used in science textbooks and literature, reinforced gender biases that are not only harmful, they are just plain inaccurate. When scientists bring in their biases about gender roles, they are actually prone to fail to observe what is actually happening. By carrying these gendered assumptions with them to their research, scientists often won’t even attempt to look for physiological evidence that something different may be occurring, leaving all of us misinformed.
It’s actually quite comical the lengths people will go to in order to hold onto these tired and inaccurate representations of sperm. The next time you hear someone telling the familiar story of sperm battling it out to the finish line, you may just want to politely correct them.
Sex (Re)Education is a weekly series in which we debunk myths you learned during sex education back in grade school and high school.