An Argument For Monogamy

This last week in my Human Sexuality class we were discussing difference in sexual behaviors and preferences between men and women. We already discussed gender differences in general a couple of weeks ago, so this time we were only talking about sexual behaviors specifically.

During the course of our discussion our professor brought up a theory that argues women are biologically driven to cheat during their most fertile days of the month. Some of you may have heard of this study before where you have women rank the attractiveness of various pictures of men during different points of their cycle. An alternative method is to have them take pictures of men on a computer that can be manipulated to adjust basic features (jaw line, brow, nose, etc.). What they've found is when women are menstruating or during normal days they prefer men's faces that are slightly feminine; however, when women ovulate they prefer faces that are more strongly masculine.

The researchers who did this study then argued that women must have a biological drive in them to find spouses who can take care of them, but when it comes to getting pregnant, may secretly look elsewhere for better genes. (A sad fact of DNA genealogy projects is that there is about a 10% paternity discrepancy, meaning about one in ten people are not biologically related to the man they think is their father).

I was not about to let this theory go unchallenged though so I asked the teacher about a specific study I had read about once that presented a biological argument for monogamy. He had never heard of it before but told me if I found it he would like to read it. Well, find it I did, and since I can't link to it because I found it on one of those proprietary campus search engines, I'll summarize it for you all here:

The study was done at the University of Adelaide in Australia to try and figure out why some women with perfectly healthy reproductive organs had repeated miscarriages. What they discovered was that their partners didn't produce a specific protein in their semen (only about 1% of semen is sperm). When trying to figure out what this protein is they realized it had implications beyond simply miscarriages. You see a pregnancy is a lot like an organ transplant, it is a body of foreign material growing inside of a human, and human immune systems do not like foreign material. What they discovered is that this protein tells a women's body that the DNA from her husband is permissible and not a hazard to her system. The thing is though, is that it doesn't work perfectly until there has been a critical mass. One thing that I think a lot of us know is that for a good number of people, that a first pregnancy is a bit tricky in terms of conception. In addition, if a women becomes pregnant within 4 months of her first sexual encounter with a specific man, the incidence of preeclampsia is 40%, while those who waited 12 months or more only had an incidence of 5%. Preeclampsia is in terms of symptoms very similar to organ transplant failure.

Well, I hope you all found that interesting. My professor did, I got 2 extra credit points for my effort. Of course, it would mean a whole lot more to me if this information became a part of his regular lecture.