Oral Contraceptives: They’ll Kill Your Libido and Your Men
The first study surveyed 1086 German medical students via an online questionnaire. The women were evaluated for several measures of female sexual dysfunction, including difficulty achieving orgasm, sexual desire, sexual satisfaction, lubrication, pain during intercourse, and arousal. They were also surveyed about a number of possible contributing factors, such as smoking, pregnancy, stress, relationship quality and of course, contraceptive use. 87.4% of respondents had used some form of contraception in the past 6 months; 69.5% of those used oral contraceptives, 22.5% used condoms, and 7.3% used a vaginal contraceptive ring. Most of the respondents were in a relationship and almost all (97.3%) had been sexually active in the 4 weeks preceding the study. For comparison, the participants were broken down into three groups, those who used oral contraceptives (752), those who used non-oral hormonal contraceptives (105), those who used non-hormonal contraceptives (268), and those who used no contraceptives at all (I have no idea, the previous numbers are non exclusive since women could use more than one form of bc and the exact number of non-users isn't given in the paper). These groups aren't exactly random, since birth control method is a personal choice and therefore affected by personality and the groups in addition are not equal in size, making comparison slightly tricky. On overall measures of sexual dysfunction, the numbers for all groups look fairly similar to my eye, but the statistical analysis indicates women on hormonal birth control had lower scores for with those using non-oral forms having the lowest. Women on hormonal forms of birth control scored significantly lower with respect to desire and arousal. Stress or a cigarette habit also led to lower scores, although the effect was not as strong as seen for oral contraceptives. On the other hand, there was a positive relationship between frequency of sex and overall sexual satisfaction, so there's always the shotgun strategy if you're trying to increase your sexual satisfaction.
I've heard enough personal testimony to convince me that birth control can in fact decrease a woman's sex drive, but this study isn't without problems. For one thing there is the aforementioned lack of randomness in the sample. There is also the possible impact of other factors - women who were in stable relationships were more likely to be on birth control, for example, and length of relationship was found in the same study to correlate with decreased sexual function scores. Oral contraceptives show a much stronger negative correlation with sexual function than any other measure looked at in the study, but the apparent relationship is cumulative and in actuality while many women do experience a loss of libido when they take oral contraceptives, not everyone on the pill will have these negative side effects. It's something that should always be taken into account when dealing with sexual problems, but oral bc isn't a guaranteed libido killer.
As for that second study...excuse me a moment while I remove the kid gloves....you guys. YOU GUYS. The researchers looked at previously acquired data on the incidence of prostate cancer rates and contraceptive use (separate studies, nobody's really combined the two in a single survey, seeing as virtually no one with a male prostate is on hormonal bc). They plotted the two things against each other and...voila! A correlation! Did they measure hormone levels in the men to determine if those with prostate cancer were more likely to have higher levels? No. Did they eliminate all other possible factors that might lead to both increased oral contraceptive use and prostate cancer? Not really, though they did at least control for age. Did they even compare any separate types of cancer to establish a control? Nope. Nothing.
These chemicals do end up in our water supply, along with any number of other chemicals we in the Western world ingest on a regular basis, so it is feasible that men could be exposed to higher levels of female hormones, but a simple correlative study isn't really going to give definitive proof that that is causing anything (not even the moobs that are regularly attributed to the same contraceptive-laden purified-urine all of us tap water drinkers use). The researchers also suggest a possible sexual transmission, though it isn't clear how this is in any way related to contraceptive use. Especially since the correlations they do see apply only to oral bc and not any other form of birth control. To their credit, the authors don't actually claim that the study is definitive. They state up front in the discussion section that at most the results could be seen as a basis for a hypothesis that needs considerable testing, but of course you wouldn't know that from the reporting out there, which makes it sound like the researchers are implying that the whorish behavior of Western women is leading men to develop prostate cancer. They're not. It's kind of a stunt study, easy to do since it just means running other people's data through some statistics and great for generating publicity but it's scientific merit is close to zero.
So there you have it: the horrible effects of oral contraceptives on women's libido are real, though slightly exaggerated by the media. The effects on men's prostates are probably strictly imaginary. Though I suppose there is a chance there's a relationship, there's nothing in the current study that makes me think the idea has any merit.