Episode 46 Ovists vs. Spermists: The Discovery of Fertilization

Fertilization, conception, the miracle of life. The conjoining of egg and sperm. Women have been having babies since the beginning of time, so it makes you wonder. Did people always know where babies come from? Spoiler alert: they had no idea. Join us in this episode to see how famous physicians like Galen and Hippocrates were woefully wrong about reproduction, how pond water led to the discovery of sperm, and how the science community was convinced tiny people lived inside of us. The journey to discovering fertilization is full of wrong turns and dead ends, but eventually, scientists found the way.

Feminist Corner:

  • How did the scientist’s own preconceptions and beliefs affect the path to this discovery? Were there any common themes?

Listen to the episode, discuss these questions with friends and family, let us know what you think!

Show Notes:

You would think that since humans have always had sex, they would have some idea about where babies come from. But you would be wrong. So today let’s go on the journey to discover fertilization. 

Sex ed 101. When a female ovulates, she releases an egg that lives in the fallopian tube. From there, the egg is either discarded in menstruation or fertilized by sperm after sexual intercourse. But scientists didn’t know this for a very long time. So what was known? 

Throughout history, there have been ideas thrown around about where babies come from. One common idea was that women were a barren field with nothing to offer. To juxtapose that, it was also believed that anything a woman saw, ate, or even thought about could affect the baby. This theory was believed to the point that doctors truly thought a woman was giving birth to dead rabbits. Yes, bunnies. 

Moving onto classical times, people began to think more scientifically about these theories. Everyone knew that semen came from men. But what was in it? What did it contribute? Then if men had something to contribute, then maybe women did too. So scientists began to study female animals in the hopes of finding an egg and then maybe even an embryo! From studying deer to bugs, they looked across the animal kingdom. And finally, the Ovists emerged. Claiming that the egg is the source of life. 

Soon after, a man by the name of Leeuwenhoek took a look at some pond water and discovered ‘animalcules’. His discovery of microbiology led to the discovery of sperm. And within the sperm, lay small little people, The idea that humans were pre-formed inside sperm branched from the idea of ‘generation’. It wasn’t until the field of genetics began by famous scientists such as Mendel and Friedrich Wolff that this theory was discounted. 

Scientists fought for generations over whether the sperm or the egg was what created life. But turns out, both of them were right. Cause who can say which one it really is? Much like the age-old question: the chicken or the egg?


Cobb, M. (2012). An amazing 10 years: The discovery of egg and sperm in the 17th century. Reproduction in Domestic Animals, 47, 2–6. https://doi.org/10.1111/j.1439-0531.2012.02105.x

Dolnick, E. (2017). The seeds of life. from Aristotle to da vinci, from Sharks’ teeth to frogs’ pants, the long and strange quest to discover where babies come from. The Perseus Books Group.

The Embryo Project Encyclopedia. A History of Embryology (1959), by Joseph Needham | The Embryo Project Encyclopedia. (n.d.). Retrieved March 18, 2023, from https://embryo.asu.edu/pages/history-embryology-1959-joseph-needhamEncyclopedia.com. (2023, March 18). Science and its times: Understanding the social significance of scientific discovery.

Encyclopedia.com. Retrieved March 18, 2023, from https://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/watching-life-begins-discovery-mammalian-ovum-and-process-fertilization

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