Here's the summary so far: If you want to maximize your sexual health, or your sexually-induced health, then engage in as much penile-vaginal intercourse as possible, using the missionary position in your bedroom at home without a condom. There's only one problem, though. None of the studies described above would qualify as top-shelf medical research. Even Irwin Goldstein, editor-in-chief of the Journal of Sexual Medicine, admits the evidence is flimsy: “This is sort of, you find what you want to find. The papers are controversial. It’s a lot of anecdotal work.”
Some have criticized Stuart Brody’s work in particular as showing a bias toward specific heterosexual acts. (“He’s obsessed with PVI,” one expert told me.) But almost all the studies in this area suffer from a suspect methodology. First, they tend to rely on self-reported figures for sex and orgasm frequency. If you want to believe the results, you'll also have to believe that the people surveyed gave completely honest information about their sex lives to total strangers. For the studies examining links between prostate cancer and ejaculation frequency, you must also trust the participants to tabulate and report their average numbers of ejaculations per month over a span of several decades.
Even if the self-reported numbers were accurate, most of these studies would still be too small to produce anything more than suggestive correlations. Vascular disease is a common cause of impotence. Does sex make men’s hearts healthier, or do healthy hearts and blood vessels simply enable men to have more sex? Standard sex-and-health research can’t answer basic questions like this.
For more solid answers to questions of sex and health, researchers would need to randomly assign people to engage in various sex acts, then see how their health fares. Such studies might compare PVI to oral sex, masturbation, or stimulation with a vibrator to find out once and for all if standard heterosexual intercourse is really as superior as Brody asserts. Randomized trials, especially ones that included gay men, could help clarify semen’s potential as an antidepressant, but such trials might be difficult. How would you ensure that participants are complying with your instructions? What if a couple breaks up before the study is over? Could a participant who’s getting sex on the side skew the results?
Existing work involves people who’ve chosen to have sex on their own accord, and (for the most part) at a frequency of their choosing. It’s not clear that participants would get the same benefits if they were having sex because it was prescribed to them by a doctor. It’s hard to imagine that having sex you don’t desire (or with a less-than-eager partner) would enhance your health—or your relationship.
But I have a bigger complaint about these studies. I normally find sex an alluring topic, but a few pages into Brody’s 26-page tome, I found myself losing interest—not just in his tedious explanations or his obsessive devotion to PVI, but in whatever health benefits sex might really offer.
Turning sex into medicine takes all the fun out of it. I don’t have sex because it’s good for me. I have sex because it’s awesome. My husband and I have sex as frequently as we do because we’re attracted to one another and crave the intimacy and intense pleasure that comes from rubbing our naked bodies together, not because we’re on some healthy sex prescription plan. It’s the desire itself and the pleasure of giving in to it that make sex wonderful. I don't doubt that frisky urges are a sign of good health (unless you've been bitten by a rabid animal), but those of us who want to get laid shouldn't need a doctor's permission to do so.