According to the Guttmacher Institute, 27.5% of all U.S. women who use contraceptives choose the birth control pill as their pregnancy-prevention-plan of choice, while another 10% use some sort of hormonal birth control in the form of a patch, inserted device (like an IUD), or an injection.
And while the prevalence of birth control among sexually active women isn’t surprising, one commonly overlooked side effect of hormonal birth control is:
It may be leading women to choose the wrong partners.
All forms of hormonal birth control work by synthesizing either a combination of the the man-made forms of the hormones estrogen and progesterone (found in brand name pills like Ortho Tri-Cyclen or Yasmin) or the “low-dose” form of birth control that contains progesterone only (like Norethidrone, often given to breastfeeding mothers) in a woman’s body.
Basically, by raising the levels of estrogen and progesterone in a woman’s body, either in steady or fluctuating levels, birth control works by “tricking” a woman’s body into thinking she’s pregnant.
When a woman is pregnant, her body will naturally produce higher levels of progesterone and estrogen to you know, grow another human being, but those high levels of hormones also trigger her body to shut down its baby-making production line by stopping ovulation. After all, it doesn’t work in nature’s favor to have a woman who’s already pregnant getting pregnant again.
And now that we’ve all enjoyed that little science lesson, here’s the concern that was raised a few years back about how birth control can actually affect how women go out looking for love:
When women aren’t on birth control, they are designed, at a purely biological level, to seek a mate that is genetically different and in some instances, superior, to themselves– nature’s way of ensuring a diverse gene pool and better natural selection. Researchers have discovered this by looking at women during ovulation; when women are ovulating, they unconsciously rate males that display more symmetrical faces and are genetically different from them as more attractive. Without realizing it, they consider those men more attractive based on information they derive from their heightened sense of smell, a super trait that women have during ovulation, specifically for the purpose of literally “sniffing” out a good mate–the males’ scents contain a “blueprint” that broadcasts their genetic differences to women.
Women on birth control, however, displayed no preference between asymmetrical vs. symmetrical faced men, nor were they able to pick up on the smell of the men putting out their genetically different body odor, leading one researcher to conclude that, “…the pill may actually upset normal preferences for choosing mates.”
Again, it comes down to simple science–when women are pregnant, their immune systems are actually lowered, so it makes sense that they would then naturally seek out people who are genetically similar to them–those people would most likely be family members who could help them with the baby and have the added bonus of not carrying any crazy diseases that might put them in danger. Score!
So if birth control is taking away those key pieces of biological and natural selection to help women choose the “perfect” mate, are women dooming mankind forever?
Another, more recent study, found conflicting evidence against the theory that birth control makes women physically incapable of choosing a compatible mate. This team of researchers, who looked at a larger-sized sample than the original study, found that women on birth control did not show a preference for genetically similar mates. However, the team did identify a “decreasing preference” for genetically-differing males in the birth control women–which to me, sounds a lot like the original study.
I guess only time will tell if birth control users end up producing genetically weak children incapable of fighting off the next deadly disease lurking out there. After all, as the study concluded,
“Humans are evolving, just as every other species, particularly when it comes to sexual selection.”
Image via M.Markus/Flickr