Before science was able to shed light on human reproduction, most people thought new life arose through spontaneous generation from non-living matter. That changed a smidgen in the middle of the 17th century, when natural philosophers were able (barely) to see the female ovum, or egg, with the naked eye. They theorised that all life was spawned at the moment of divine creation; one person existed inside the other within a woman’s eggs, like Russian nesting dolls. This view of reproduction, called preformation, suited the ruling class well. ‘By putting lineages inside each other,’ notes the Portuguese developmental biologist and writer Clara Pinto-Correia in The Ovary of Eve (1997), ‘preformation could function as a “politically correct” antidemocratic doctrine, implicitly legitimising the dynastic system – and of course, the leading natural philosophers of the Scientific Revolution certainly were not servants.’
One might think that, as science progressed, it would crush the Russian-doll theory through its lucid biological lens. But that’s not precisely what occurred – instead, when the microscope finally enabled researchers to see not just eggs but sperm, the preformation theory morphed into a new, even more patriarchal political conceit: now, held philosophers and some students of reproduction, the egg was merely a passive receptacle waiting for vigorous sperm to arrive to trigger development. And sperm? The head of each contained a tiny preformed human being – a homunculus, to be exact. The Dutch mathematician and physicist Nicolaas Hartsoeker, inventor of the screw-barrel microscope, drew his image of the homunculus when sperm became visible for the first time in 1695. He did not actually see a homunculus in the sperm head, Hartsoeker conceded at the time, but he convinced himself that it was there.
More powerful microscopes eventually relegated the homunculus to the dustbin of history – but in some ways not much has changed. Most notably, the legacy of the homunculus survives in the stubbornly persistent notion of the egg as a passive participant in fertilisation, awaiting the active sperm to swim through a hailstorm of challenges to perpetuate life. It’s understandable – though unfortunate – that a lay public might adopt these erroneous, sexist paradigms and metaphors. But biologists and physicians are guilty as well.
It was in the relatively recent year of 1991, long after much of the real science had been set in stone, that the American anthropologist Emily Martin, now at New York University, described what she called a ‘scientific fairy tale’ – a picture of egg and sperm that suggests that ‘female biological processes are less worthy than their male counter-parts’ and that ‘women are less worthy than men’. The ovary, for instance, is depicted with a limited stock of starter eggs depleted over a lifetime whereas the testes are said to produce new sperm throughout life. Human egg production is commonly described as ‘wasteful’ because, from 300,000 egg starter cells present at puberty, only 400 mature eggs will ever be released; yet that adjective is rarely used to describe a man’s lifetime production of more than 2 trillion sperm. Whether in the popular or scientific press, human mating is commonly portrayed as a gigantic marathon swimming event in which the fastest, fittest sperm wins the prize of fertilising the egg. If this narrative was just a prejudicial holdover from our sexist past – an offensive male fantasy based on incorrect science – that would be bad enough, but continued buy-in to biased information impedes crucial fertility treatments for men and women alike.