What is the purpose of the hymen?

Dear Cecil: What is the purpose of a hymen in a woman? Ever since the painfulness of my own being broken during my first sexual intercourse, I’ve tried to find this out. Several gynecologists I asked simply shrugged — they never even wondered about such a thing. (Needless to say, they were men!) I once had a teacher at college who postulated that the hymen was some sort of genetic aberration that had been reinforced once men discovered it. The idea was that the girls who had a hymen were the ones chosen as brides, since they could prove they were virgins, a valuable asset when dealing with a patriarchal culture that must be certain that a woman’s children were really her husband’s, not some previous lover’s. (In some societies it was customary on the morning after the wedding night to hang out the bed sheet to show the hymen’s blood.) The women with hymens passed them on to their daughters, while those without weren’t chosen as brides and didn’t reproduce as frequently. So hymens became the common thing. Any truth to this theory? Nancy J., Montreal, Quebec

Cecil replies:

I feel a professional duty to state the matter as simply and clearly as I can, Nance. I don’t know. What’s more, anybody who tells you he (or she) does know lies like a dog. Figuring out what this or that anatomical feature is “for” is what scientists do at parties when they’re tired of charades. All you get are a lot of untestable hypotheses and maybe a couple talk show bookings for whoever is lucky enough to dream up a theory picked up on by the press. But it ain’t science.

Most writers on the evolution of sex are mum regarding the purpose of the hymen, but occasionally you’ll get somebody who’ll take a flier — your teacher, for example, or the indefatigable Desmond Morris. In The Naked Ape Morris writes: “[A] feature … that appears to be unique to our species is the retention of the hymen or maidenhead in the female. In lower mammals it occurs [only during development of the embryo]. Its persistence [in humans] means that the first copulation in the life of the female will meet with some difficulty…. By making the first copulation attempt difficult and even painful, the hymen ensures that it will not be indulged in lightly. [Young males are inclined to have sex without making any long-term commitment.] But if young females were to go so far without pair-formation, they might very well find themselves pregnant and heading straight toward a parental situation with no partner to accompany them. By putting a partial brake on this trend in the female, the hymen demands that she shall have already developed a deep emotional involvement before taking the final step, an involvement strong enough to take the initial physical discomfort in its stride.”

Just one problem: Morris to the contrary notwithstanding, retention of the hymen is not unique to humans. It occurs in horses, whales, moles, mole-rats, hyenas, and perhaps other animals. (In the great fin whale, in fact, the hymen is not completely destroyed until childbirth.) Why? We haven’t got a clue. “Such adaptations [i.e., retention of the hymen] are explicable only if the male of the species finds it to his advantage to seek a virgin,” Bettyann Kevles observes in Female of the Species (1986). “But there is no evidence that mammal males seek inexperienced females, and no evidence that females with this peculiar anatomical feature remain monogamous. … In whales, one can explain the resealing of the vagina as a means of keeping water out of the reproductive organs.”

Not the world’s most satisfying answer, I agree. But we don’t even know why women have orgasms. Morris’s preposterous theory: orgasm keeps women on their backs afterward, grinning with satisfaction, whereas if they were up and about right off the bat, the semen and with it their chances of reproductive success would dribble down their legs. Sounds like something I’d make up. But the difference is, I’d wink.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.