“Vaginal exposure to semen elevates women’s mood.
Perhaps you’re familiar with the McClintock effect, the observation that when groups of reproductive-age women live or work together (in college housing, the military, all-female workplaces, etc.), over time their menstrual periods tend to become synchronized. The accepted explanation is that the women detect each other’s pheromones, subtle scents that each of us produce, and somehow these only-faintly aromatic but powerful compounds influence the women’s hormones and make their menstrual periods arrive around the same time.
But at the State University of New York, two evolutionary psychologists were puzzled to discover that lesbians show no McClintock effect. Why not? Gordon Gallup and Rebecca Burch realized that the only real difference between lesbians and heterosexual women is that the latter are exposed to semen. They speculated that maybe semen chemistry has something to do with the McClintock effect. But if that were true, the vagina would have to absorb compounds in semen that affected the women’s pheromones. […]
Vaginal tissue is very absorptive. It’s richly endowed with blood and lymph vessels. Given vaginal absorptiveness and all the mood-elevating compounds in found in semen, Gallup, Burch, and SUNY colleague Steven Platek wondered if semen exposure might be associated with better mood and less depression. They surveyed 293 college women at SUNY Albany about intercourse with and without condoms, and then gave the women the Beck Depression Inventory, a standard test of mood. Compared with women who “always” or “usually” used condoms, those who “never” did, whose vaginas were exposed to semen, showed significantly better mood–fewer depressive symptoms, and less bouts of depression. In addition, compared to women who had no intercourse at all, the semen-exposed women showed more elevated mood and less depression.”
But, as stated in the study: “It is important to acknowledge that these data are preliminary and correlational in nature, and as such are only suggestive. More definitive evidence for antidepressant effects of semen would require more direct manipulation of the presence of semen in the reproductive tract and, ideally, the measurement of seminal components in the recipient’s blood.”
See more at Scientific American:
Bering, J. “An Ode to the Many Evolved Virtues of Human Semen,” Scientific American, Sept. 22, 2010.
…or the study itself: