In last week’s “Savage Love” column, Dan Savage urged readers to Google “sperm competition” for some enlightenment on sex and the male psyche. Now I don’t always agree with Dan’s advice, but when he challenges me to Google something, I really can’t resist (as you might imagine, this has led to all kinds of horrifyingly icky–yet fascinating!–revelations). And I must say, what I learned seems to have all kinds of interesting implications.
Sperm competition is, simply, the race between the sperm of two or more males to fertilize an ova. And thanks to evolution, the male animal–including the male homo sapiens–has natural adaptations that maximize the chance of his sperm getting to the finish line first.
Consider this, from the magazine New Scientist:
Men who view pornographic images of two men and a woman produce better-quality sperm than men viewing pornographic images of just women, an Australian study reveals.
The finding suggests that humans may be capable of subconsciously increasing semen quality when faced with the possibility that their sperm will have to outrun those of other men in a woman’s reproductive tract.
In the study, zoologists Leigh Simmons and Sarah Kilgallon of the University of Western Australia in Perth asked 52 heterosexual men aged between 18 and 35 years to ejaculate into a container after viewing the two types of image. The volunteers had previously abstained from sexual activity for two to six days. In samples from men who viewed the images containing the two men and a woman – the “sperm-competition” images – 52% of the sperm were motile. This compared with 49% sperm motility in the men who viewed the images of women only – a difference that was statistically significant after taking into account lifestyle factors such as cigarette smoking and alcohol consumption.
Oh, there’s so much of interest here. First of all, it would appear that girl-girl porn actually reduces sperm motility! If you’re the porn industry, you probably want to bury that info as fast as possible. Secondly, it confirms that sperm competition is so hard-wired–no pun intended, I swear!–that the presence of other men during sex, even if it’s only self-sex and the other men are on a screen, gets those swimmers swimming like single-cell Michael Phelpses.
Does this explain why ex-boyfriends tend to resurface when they know you’re dating someone new? If even implied competition makes their sperm more aggressive, does the urge somehow work its way north and lodge in the brain, thus accounting for drunken phone calls and late-night emo-mails? I wonder. After the end of both my last two serious relationships, I was happily shtupping away with a new beau when my ex decided he wanted another try. The first I did not take back, the second I did, but lived to regret it. If only I’d known it was just his sperm talking…