Saturday, January 30, 2010

Interesting effects of the Pill

I was in college when I first heard about the sweaty t-shirt research. Our immunology professor was teaching us about MHC genes, which code for proteins that present foreign antigens to immune cells as part of protecting our bodies from invading viruses and such. Theoretically it's advantageous to procreate with someone whose MHC genes are dissimilar from yours, to give your children a robustly diverse set of immune genes with which they can tackle a greater variety of potential threats.

So, scientists had a group of men wear t-shirts for a while, and then they gave the shirts to women to smell. The women picked out the men they thought they'd be attracted to, based only on their scent. And it turned out they'd picked men with dissimilar MHC genes to their own. Isn't that crazy? They could tell by the smell!

Well, more recently I found out what happened when those same women starting dosing themselves with the hormones in the birth control pill. They began to pick the wrong men:

After taking the pill, women shifted toward preferring genetically similar men. Women who did not take the pill slightly increased their preference for genetically different men....

The question, of course, is what happens when a woman taking birth control pills marries a man to whom she's attracted -- and then stops taking the pill.

Herz says marriage counselors who have never heard about these studies tell her that the No. 1 complaint among women no longer sexually interested in their husbands is that they can no longer stand how he smells.

And women aren't the only ones influenced in this way. Men are more attracted to women who are ovulating, and the scent of them triggers a testosterone surge. Pill users don't get that invisible pheromonal advantage in the middle of the month, since the Pill stops ovulation. This has a bearing on the next article too, in which a scientist speculates that the Pill is responsible for the shift from the masculine movie stars of the sixties to the baby-faced stars of today. Women prefer more masculine-looking men when they're ovulating, so it's a reasonable theory that a nation with more Pill usage and fewer ovulating women would begin to prefer less masculine-looking movie stars. I wonder if that's also why beards have fallen so far out of fashion?

Even the environment is affected by all this. Male fish in our rivers are becoming feminized, and studies have linked this to all the female hormones in the Pill that eventually seep into the water supply. Which leads to a disturbing question: if all the extra estrogen does that to male fish, what is it doing to male humans? According to research I remember but am too lazy to look up, infertility is a much greater problem than it used to be, even after accounting for the higher average age of marriage, and the human male sperm count has been dropping for decades.

Environmental problems and t-shirt studies aside, I wouldn't use the Pill not only because it's a contraceptive but because it's an abortifacient. That is, it not only acts to prevent ovulation (and thus conception), but when breakthrough ovulation occurs anyway and the resulting egg is fertilized, it's unable to implant in the womb because of how the Pill's hormones affect the lining of the uterus, so the embryo dies instead. That information needs to become much better known, since it's very pertinent to the decision of anyone who believes that life begins at conception!

But anyway, I find all this research fascinating. How do you like knowing how much you're affected by your hormones? Or better yet, by invisible, odorless pheromones, wafting from someone else's body, right up into your nose? I've encountered this whenever I live with other young women and we find our cycles synchronize... and it's just weird!


Rachel Ann said...

Wow. This was a FASCINATING post! Thanks for posting it!

Pam H. said...

I'd heard the research before, and wanted to point out that the part about the Pill being the cause of the fishes' feminization is being denigrated, to make it the fault of other chemical pollutants emitted by Industry. Even though there's a larger likelihood that, considering how many women use the Pill, it's ending up in a larger percentage of waters, in larger doses than other chemicals. (It's bound to be eliminated in urine, I'd think.)

Mentioning, too, that Depo-Provera is also an abortifacient, even though a Catholic O.B. told me it wasn't. I sat in his office and read the literature, which said the very thing you mention about the Pill, and got up and walked out and never went back.

Rachel Gray said...

Thanks Rachel. :)

Pam, about people not believing the fish feminization studies are due to the Pill, I thought I remembered reading that at least in one study they actually detected the estrogen/progesterone in the water-- I'd have to research that to be sure.

That O.B. you encountered sounds like a lot of people who don't want women to make fully informed choices, but instead paternally withhold important information. They make the moral decision and don't allow their patients to do so for themselves.

Anonymous said...

Good post. Though I'm not really sure about the macho/babyfaced guys thing, I've always been attracted to sensitive-looking men and I've never been on any pills.

I'm scared what these chemicals do to my body if they really get into drinkwater...

Rachel Gray said...

Yeah, and the article I linked admits that there's a whole lot more to attraction than just pheromones and hormones-- thank goodness!