Emily Martin is an anthropologist. She published a short essay in 1991, entitled The Egg and the Sperm: How Science Has Constructed a Romance Based on Stereotypical Male-Female Roles.

In her essay, Martin observes that biologist have employed cultural stereotypes in their descriptions of sexual reproduction. For example, the sperm is overwhelmingly seen as the "active" party, and the egg is the "passive" party: the sperm moves, while the egg simply waits for the sperm's arrival. The sperm is the knight in shining armor, and the egg is the damsel in distress.

The female process of ovulation is portrayed as "wasteful" and "unproductive" (since a woman has all the eggs she will ever have at the beginning of her life, and "loses" them during menstruation), whereas the male process of spermatogenesis is "magnificent" and "productive" (since a man produces millions of sperm every day). The inconsistency is obvious: why is a woman's menstrual cycle seen as wasteful but a man's production of millions of sperm every day not?

The active/passive roles also commonly carry other disturbing metaphors. The sperm "invades" the fallopian tubes, "penetrates" the egg, "forcing" its way into the nucleus. Activity and passivity correspond to dominance and submission.

However, discoveries in the 1980s shown new light on the process of fertilization. The sperm, far from being energetically propelled forward by the whiplash motion of its tail, primarily moves from side-to-side; this has been theorized as a means to escape from sticking to cells. The egg has a specialized surface layer that prevents the sperm from escaping, it functions as a kind of "sperm-catcher".

This new imagery gives the egg an active role, but at the cost of introducing yet another cultural stereotype, that of a spidery femme fatale trapping a helpless man. If the female aspect is passive, then it is submissive, and if it is active, then it is dangerous. Furthermore, if the male aspect is active, then it is heroic, and if it is passive, then it is a victim. Interestingly, it seems like passivity in general corresponds to victimhood in some way.

Martin ends her paper with an appeal that we need to wake up these sleeping metaphors and see them as they are.

I think her analysis is good, and can be extended beyond the sperm and the egg. For example, the penis is predominantly seen as the active member, the vagina the passive. The penis penetrates the vagina, it does the work while the vagina simply receives its thrusts. However, it is possible to see the penis in a more passive role, as a "guest" in a vagina, the vagina being the welcoming "host". In fact, the biology behind the vagina shows it to be involved in a complex system of motions, expansions and contractions, that make it equally as active as the penis.

The trouble, as I see it, is that humans conceptualize the world in terms of metaphors that have teleological content, and it seems impossible to me to get away from this. Biological things are best represented as having a function with respect to an overall system. The best thing we can do is move to a view that treats biological mechanisms as evolving processes that go through phases that can be interpreted metaphorically; both the penis and vagina display passive and active behavior. More importantly, we can also see them as a cooperative system, both working together to achieve a goal, i.e. the continuation of the species.