Brit Trogen

New York, New York


previewIn 1991, anthropologist Emily Martin argued that accounts of human fertilization in medical textbooks often applied gendered language and stereotypes to anthropomorphized representations of the sperm and egg.1 “Masculine” sperm were depicted as strong adventurers, heroes, and conquerors, actively swimming towards the egg and “penetrating” its defenses.1 “Feminine” oocytes, on the other hand, are described as passive and fragile, being “swept” along the fallopian tubes to await the arrival of the sperm.1 Twenty-five years later, this distinction persists in popular portrayals of fertilization.2 The origins of these metaphors extend back to antiquity, with Aristotle’s Generation of Animals as one of the key popularizers of the idea of “passive” female contributions to conception.3 Examining the role of gender bias in Aristotle’s account of fertilization provides a model to appreciate the social influences underlying modern accounts of fertility.

The tenacity of gendered accounts of the egg and sperm are not, it should be noted, rooted in science. Gametes are unicellular and, necessarily, characterless, thoughtless, and free of conscious motivation. Furthermore, decades of scientific research support a far more active role for the egg in fertilization than is typically acknowledged. Though sperm swim several millimeters per second, contractions of the uterine walls and fallopian tubes are crucial in rapidly propelling the sperm along its path; eggs secrete chemicals that attract, guide, capture, and “pull” the sperm towards them; other chemicals produced in the female body trigger hyperactivity in the sperm and contribute to gamete fusion.Fertilization is a cooperative process, with both the female body and the egg cell making active contributions to its completion. Gendered depictions of the egg and sperm thus rely on “stereotypes central to our cultural definitions of male and female.”Rather than being based in biological reality, these depictions reflect broadly held views on the expected roles of men and women in society.

Originally published around 350 BCE, Aristotle’s Generation of Animals discusses the process of conception in depth, ultimately superseding contemporary theories to shape later scientific views of fertilization.In Generation of Animals, specific roles are assigned to the male and female partners in conception according to their respective “nutritive discharges” (G.A. 729a). The male sperma provides the “principle of movement” and directs embryonic development, while the female katamenia, a less mature version of sperma, provides the raw material for growth and nourishment (G.A. 730a).

Aristotelian philosophy centers largely on a theory of causation. Four basic “causes” are said to drive all natural phenomena: the final cause, formal cause, efficient cause, and material cause. In Aristotle’s reproductive theory, the allocation of these causes to either the sperma or katamenia is used to introduce major distinctions between the roles of men and women in fertilization.In Generation of Animals, the female contribution provides only the material cause: “that out of which something existing becomes” (Physics 194b 24). The katamenia is the raw material of the fertilization process; it carries the potential for the developing human, much like a piece of wood or metal. To sperma, Aristotle attributes the remaining three causes: the formal, final, and efficient causes.5 Chief among these are the formal and final causes, which constitute a teleological explanation for fertilization, regulating the manner of change in the raw material and specifying its ultimate form.4 Finally, the efficient cause—“that from whence comes the first principle of kinetic change” (Phys. 194b 30)—is the trigger or catalyst which begins the process of development. Notably, of these four causes, the female-derived material cause is viewed as somewhat trivial; the lowest in importance in the causational hierarchy.4 “The form,” Aristotle writes, “is more important than the matter” (Metaphysics 1029a 6).

Based on this depiction of fertilization, conception and development are viewed as largely male-dominated activities, with the female contributing only passively. This fact is reflected in the “artisan” metaphor used in Generation of Animals: sperma is likened to a craftsman while the katamenia is the wood he works upon (G.A. 729b). The male is the active force in creation, while the female is the inert raw material and workspace for this activity. Sperma also endows the embryo with the “rational soul”—the intelligent, sensitive mind that distinguishes humankind from the rest of the animal kingdom (G.A. 732a). The contributions of the father alone are thus responsible for the very humanity of the developing child, the “generative force of the soul,” while the mother’s “creativity of the body” is allotted minimal importance in comparison.Indeed, as Horowitz notes, “Aristotle went about as far as one can in attributing fertility exclusively to the male sex.”The female in Aristotle’s view merely labors to fulfill the plan and design of the man: “the product of her labor is not hers.”As in modern accounts, female contributions to conception are viewed as inherently passive.

This distinction was far from accidental. Aristotle’s theories about men and women were deduced not from objective, empirical observation or scientific method—a fact epitomized by the demonstrably false claim in History of Animals that men have more teeth than women—but from a profoundly sexist worldview. Aristotle held deeply rooted beliefs on the social and political subservience of women, which overtly shaped his description of the female as biologically inferior to the male; as he writes in Politics: “The male is by Nature superior and the female inferior; the male is the ruler and the female is the subject.”5 In Generation of Animals, the female sex is characterized by the “inability” to produce true sperma, likened to a “deformed” or “infertile male,” and portrayed as inherently less mature, developed, and intelligent as man (G.A. 728a). Aristotle also saw women as inherently passive based on his view of women as submissive in the home and in society.5 Aristotle’s reproductive theory follows from this belief in an inherently circular manner: if “the male stands for the effective and active, and the female, considered as female, for the passive,” he writes, it follows that the female contribution “would not be sperma but material for the sperma to work upon” (G.A. 729a). Aristotle’s treatment of sperma and katamenia is thus wholly conflated with his belief in the acceptable roles of men and women in society.

Does the Aristotelian notion of the inferiority of women persist in modern portrayals of fertilization? In 1991, Martin noted that while the actions of sperm are frequently evaluated in “breathless prose”—variously described as “remarkable” and “amazing”—there is, she notes, an almost “dogged insistence” on casting female processes in a negative light.1 Egg-related processes are often described critically: ovulation is described as a “wasteful” enterprise characterized by constant degeneration—this, in spite of the fact that many millions more sperm are “wasted” because of  their failure to participate in fertilization.Positive images, Martin argues, are largely denied to the bodies of women.In subsequent years, and perhaps in response to these criticisms, medical textbooks and research articles shifted to using largely gender-neutral depictions of the process of fertilization.2

A 2015 study, however, found that accounts of fertilization in the general public still draw on themes of female passivity and inferiority.A narrative analysis of online videos depicting fertilization found themes consistent with gendered and anthropomorphized portrayals of the sperm and egg: sperm are “miraculous,” brave, and powerful “little men,” fighting to carry out a mission or conquest, while eggs are immobile, “featureless planets,” lacking a point of view entirely, and passively waiting for the arrival of the heroic sperm.Fertilization itself is depicted as courtship, sex, or rape, with sperm actively “cutting through,” “penetrating,” or “piercing” the egg.2 One video was explicit in the fertilization-as-sex metaphor: “the sperm tries a drill, then a jackhammer, and finally a stick of dynamite to enter the egg, and once inside, lights a cigarette and relaxes, its eyes half-closed.”Depictions of active sperm and inert eggs, echoing the Aristotelian script, are clearly still prevalent in popular depictions of fertilization.

Physicist and feminist thinker Evelyn Fox Keller wrote that gender biases in science often have a “subterranean potency,” influencing our thinking in subconscious but meaningful ways, and undermining our ability to resist their influence.The fertility example clearly shows how unintentional biases and “sleeping metaphors” edge their way into our scientific views.Gendered images in science have a doubly negative impact. First, they portray traditional gender roles as inherent and inescapable—encoded in our very cells—thus cementing the notion of the inferiority of female cells, bodies, and minds. As Nettleton notes, describing sperm as “amazing, powerful and crafty,” while ignoring the egg, allows biology to foster misogyny.2 These portrayals also clearly interfere with scientific objectivity, potentially stymying the formation of new and alternative scientific theories, and hindering innovation.Greater awareness of these biases, including their historical precedents, brings increased opportunity to overturn and reconsider these long-held and little-acknowledged beliefs. An appreciation of Aristotelian ideas and biases in the development of fertility models helps to increase awareness of these portrayals and their implications, removing some of their “subterranean” power over our thinking.


1.  Martin, Emily. "The egg and the sperm: How science has constructed a romance based on stereotypical male-female roles." Signs 16.3 (1991): 485-501.

2.  Nettleton, Pamela Hill. "Brave Sperm and Demure Eggs: Fallopian Gender Politics on YouTube." Feminist Formations 27.1 (2015): 25-45.

3.  Ross, W. D., ed. The Oxford Translation of Aristotle. Vol. 5. Trans. Arthur Platt. Oxford: Clarendon press, 1912.

4.  Boylan, Michael. “The Galenic and Hippocratic Challenges to Aristotle’s Conception Theory.”Journal of the History of Biology 17 (1984): 83-112.

5.  Horowitz, Maryanne. “Aristotle and Woman.”Journal of the History of Biology 9 (1976): 183-213.

6.  Keller, Evelyn Fox. “Gender and Science: Origin, History and Politics.”Osiris10 (1995): 26-38.


Brit Trogen received her master’s degree in medical anthropology from the London Center for the History of Science, Medicine, and Technology at Imperial College London and University College London, UK. She is currently a second-year medical student at the New York University School of Medicine.