Pheromones and contraception....

Tomorrow Night's topic at the LOGOS meeting (our 21 and up ministry) will be 'Contraception?' So, if you're of age, bring yourself and a healthy hunger for cheese. 8:10 pm in the upper room. The topic below also became somewhat of a topic with the girls in the cafe today so I figured this was an appropriate post.

Opening Pandora's Box

by Vicki Thorn

Over the past several months, a number of stories have been circulating in the print media and online that have to do with the impact of chemical contraceptives on mate choice in humans. It seems that most of the coverage is appearing in foreign media – curiously, very little media attention has been given to the issue in the United States.

In the Daily Mail in the United Kingdom, an October 8 article summarizes findings in a research paper published in the journal “Trends in Ecology and Evolution.” Researchers Alexandra Alvergne and Virpi Lumma entitled their study, “Does the contraceptive pill alter mate choice in humans?”

The following is from the paper’s abstract:

Female and male mate choice preference in humans both vary according to the menstrual cycle. Women prefer more masculine, symmetrical and genetically unrelated men during ovulation compared with other phases of their cycle, and recent evidence suggests that men prefer ovulating women to others. Such monthly shifts in mate preference have been suggested to being evolutionary benefits in terms of reproductive success.

How does this all work?

It all has to do with pheromones – the chemical signals, or scent molecules, that communicate to males a female’s most fertile time for reproducing. While there has been debate in the past about whether this means of communication exists in humans, and not just animals, many scientists who have been pursuing the elusive pheromones are certain of their existence in humans at this time. For instance, in 1995, Swiss researcher Claus Wedekind discovered that women who are not chemically contracepting preferred the odor of males whose MHC complex (Major Histocompatibility complex) – immune system markers indicated via smell – were dissimilar to theirs.

In other words, these non-contracepting women were attracted to the scent of men genetically compatible with them. To increase the possibility of fertility with a mate, we need dissimilar immune systems. This is why we do not marry our first cousins. Such an immune system similarity could lead to offspring that are not as healthy.

The use of chemical contraceptives blocks this natural phenomenon by inducing a state of “faux pregnancy,” a suppression of the normal cycling of hormones associated with ovulation. This change in a woman’s body results in changes in her attraction to a potential mate. She is now attracted to a mate whose MHC complex is quite similar to hers, more like that of her father or her brother. It seems to eliminate the adaptive attraction to a male with whom there is an increased possibility of fertility. Furthermore, chemical contraceptives eliminate the normal pheromone shift that alerts males to the woman’s time of fertility. Men find the scent of ovulating women to be attractive and arousing. A consistently infertile woman elicits no such response.

The article summary continues, “New evidence is emerging that taking the oral contraceptive pill might significantly alter both female and male mate choice by removing the mid-cycle change in preferences.”

This alteration may impact relationship satisfaction, in addition to reproductive outcomes. There is growing concern in some quarters that we may have a generation of children with compromised immune systems because of this shift in partner preference caused by chemical contraceptives.

“There is evidence that genetic similarity between couples might be linked to infertility,” Dr. Lumma – one of the co-authors of the journal articles – summarizes. From that, she says, “The ultimate outstanding evolutionary question concerns whether the use of oral contraceptives when making mating decisions can have long-term consequences on the ability of couples to reproduce.”

“If this is the case, Pill use will have implications for both current and future generations, and we hope that our review will stimulate further research on this question,” Dr. Lumma continued.

keep reading...