(Neige)
Jeanna Bryner
Senior Writer
LiveScience.com




Birth-control pills could screw up a woman's ability to sniff out a compatible mate, a new study finds.


While several factors can send a woman swooning, including big brains and brawn, body odor can be critical in the final decision, the researchers say. That's because beneath a woman's flowery fragrance or a guy's musk the body sends out aromatic molecules that indicate genetic compatibility.


Major histocompatibility complex (MHC) genes are involved in immune response and other functions, and the best mates are those that have different MHC smells than you. The new study reveals, however, that when women are on the pill they prefer guys with matching MHC odors.


MHC genes churn out substances that tell the body whether a cell is a native or an invader. When individuals with different MHC genes mate, their offspring's immune systems can recognize a broader range of foreign cells, making them more fit.


Past studies have suggested couples with dissimilar MHC genes are more satisfied and more likely to be faithful to a mate. And the opposite is also true with matchng-MHC couples showing less satisfaction and more wandering eyes.


"Not only could MHC-similarity in couples lead to fertility problems," said lead researcher Stewart Craig Roberts, an evolutionary psychologist at the University of Newcastle in England, "but it could ultimately lead to the breakdown of relationships when women stop using the contraceptive pill, as odor perception plays a significant role in maintaining attraction to partners."


Sexy scents


The study involved about 100 women, aged 18 to 35, who chose which of six male body-odor samples they preferred. They were tested at the start of the study when none of the participants were taking contraceptive pills and three months later after 40 of the women had started taking the pill more than two months prior.


For the non-pill users, results didn't show a significant preference for similar or dissimilar MHC odors. When women started taking birth control, their odor preferences changed. These women were much more likely than non-pill users to prefer MHC-similar odors.


"The results showed that the preferences of women who began using the contraceptive pill shifted towards men with genetically similar odors," Roberts said.


Pregnant state


Based on the work by Claus Wedekind, a University of Lausanne researcher who preformed similar studies in the 1990s, Roberts suggests a likely reason for the pill's effect on a woman's odor preferences. The pill puts a woman's body into a hormonally pregnant state (the reason she doesn't ovulate), and during that time there would be no reason to seek out a mate.


"When women are pregnant there's no selection pressure, evolutionarily speaking, for having a preference for genetically dissimilar odors," Roberts said. "And if there is any pressure at all it would be towards relatives, who would be more genetically similar, because the relatives would help those individuals rear the baby."


So the pill puts a woman's body into a post-mating state, even though she might be still in the game.


"The pill is in effect mirroring a natural shift but at an inappropriate time," Roberts told LiveScience.


The results are detailed in the current issue of the journal Proceedings of the Royal Society B: Biological Sciences.

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I smell a rat

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Plug me into somethin'

If the theory does not conform to the facts, then the facts must be discarded.

No good deed ever goes unpunished

Never argue with an idiot. He'll drag you down to his level, & beat you with experience.

I find myself wondering who funded this study.

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On the kinkometer, my kink measures as a sine wave.

This is good science.

Proceedings B is the Royal Society's principal research journal for biological sciences. The articles are peer reviewed. Here is the link to the Proceedings B Referee Information.

This research builds on previous work. Here is the link to the article in question.

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Eudaimonia

Not quite the point jseal.

True, while many papers make it past peer review that shouldn't, and therefore, peer review doesn't guarrantee that something which passes is "good" science, just make it much more likely that it is "good" science.

Two real points here: Point 1. OK, there's been this study. How is actual science or the practice of medicine advanced in the first place? IOW, why study this at all? It's pretty much an irrelevant aspect of human interaction.

A couple of possible reasons: 1. Just some researchers spending grant money so they can spend grant money. Scientists have to eat too, you know. 2. A more nefarious possibility is that the scientists were paid to go looking for "evidence" that supported a hidden agenda. And if you for one moment think that isn't a possibility, I have a bridge in Brooklyn to sell you.

More importantly, Point 2. Who is going to use this results of this study, and in what matter? Scientific knowledge is neutral, it just is what it is. However, the knowledge is never disseminated in a vacuum: it is always released into the world of human interaction, meaning that whatever the actual facts may be, there will always be those who will mis-use them for their own political ends.

When one digs down deep enough, one *usually* finds that the people who paid for the study got the results they were looking for; and when they don't, they find a way to twist the fact in their favor anyway.

So, no I wasn't questioning whether or not this was "good", as in, fact-based, empirically-derived science.

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On the kinkometer, my kink measures as a sine wave.

I got on the pill a few months into dating Mr. AZRH, when I was a wee lass of 19. We will celebrate our 18th anniversary of togetherness in October. And I still dig him.

I guess I'm not buying it.

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I’ll agree with you about that. As this was published in a peer reviewed journal, it does, of course, place the burden upon you to substantiate why you challenge the interpretation of the data. Remember, the Referees have accepted the recommendations of other scientists that this is a reasonable interpretation of the data.

While there are those who would agree with your comment that human breeding behavior [sexual intercourse] is “an irrelevant aspect of human interaction”, I am not a member of that group.

I presume that you are in a position to substantiate these allusions, or are they mere speculation?

I’ll agree with you that there are those who force their prejudices and political POV onto the interpretation of experimental data. I doubt that you will be able to produce evidence that the results of experiments published by the Royal Society in general are, and in this instance were predefined by the sources of the funding.

Still, I am not unreasonable. Show me your evidence, and I may be persuaded that you are not mistaken.

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Eudaimonia

jseal:

This is not the first time you have put words into my mouth.

Stop it.

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On the kinkometer, my kink measures as a sine wave.

gekkogecko,

If I interpret the above correctly, I believe that you shall provide no evidence to support your claims. I hope you will understand if I do not accept your claims without evidence.

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Eudaimonia

This is the third time that you have, in recent memory, put words into my mouth.

Yesterday, I demanded that you stop this tactic.

Instead, you repeated it.

That is offensive trolling.

My respect for you as a person just dropped to zero.

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On the kinkometer, my kink measures as a sine wave.

gekkogecko,

Everyone is entitled to their opinion.

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Eudaimonia

*- edited for reality

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Plug me into somethin'

If the theory does not conform to the facts, then the facts must be discarded.

No good deed ever goes unpunished

Never argue with an idiot. He'll drag you down to his level, & beat you with experience.

You are mistaken.

If you take the time to read the thread with care, you will notice that gekkogecko, AZRedHot, and I each stated our opinion. You might also notice that the opinions that under scrutiny have been gekkogecko’s, and then only because he was unable to leave well enough alone. AZRedHot and I also provided reasons for our opinions. OK. Fair enough; it is possible for reasonable people to disagree. As it then stood, that was that.

Not satisfied with expressing his own opinion, he then proceeded to challenge mine.

gekkogecko led off his next post with “Not quite the point jseal.” This presumes that the point was something other than if the work in question was good science, as was my opinion. gekkogecko mistakenly assumed that his POV was the correct one, and mine was not.

He then questioned the validity of the study “… why study this at all? It's pretty much an irrelevant aspect of human interaction”. The notion that a study of one of the drivers of human mate selection is irrelevant is laughably immature. Very few things are more important to animals than to breed. Learning what drives them to make the selections they make, and how to avoid potential problems is vital.

He then presented two possible justifications for the study, both of which impugn the ethics of the authors of the study; “spending grant money so they can spend grant money”, or that they “were paid to go looking for "evidence” that supported a hidden agenda.”. He followed that with a non sequitur, “… if you for one moment think that isn't a possibility, I have a bridge in Brooklyn to sell you.” I had not raised the question, let alone suggested that it was not a possibility.

I shall ignore the red herring as to how the results may or may not be used. How knowledge gained from this study will be used does not change the science the authors presented.

He then asserted that “When one digs down deep enough, one *usually* finds that the people who paid for the study got the results they were looking for”. A bold claim – if it were true. Note that he has been either unwilling or unable to show that this is a fact, although I have asked him to do so.

Further, he used the word *usually*. Not *seldom*. Not *infrequently*. Not *occasionally*. No, he used *usually* to describe the frequency that one “finds that the people who paid for the study got the results they were looking for”. Let us assume that he meant what he wrote. Looking up "usually" in a thesaurus, I find it defined as "In an expected or customary manner; for the most part." Synonyms for it are: commonly, consistently, customarily, frequently, generally, habitually, naturally, normally, often, regularly, routinely, typically.

Given this generally accepted used of the word usually, we might then reasonably ask if this is true for the journal in question. The publications of the Royal Society are in England as those of the American Association for the Advancement of Science are here in the States. The Royal Society is THE independent scientific academy of the UK. I can only presume that gekkogecko is unfamiliar with the subject material. I cannot believe that he would advance such a bizarre notion otherwise.

geckogeck is entitled to his opinion, as is AZRedHot, and as am I. He is not entitled to take me to task for expressing my opinion, while presuming that his opinions are somehow sacrosanct.

You are mistaken scotzoidman. It was not about my opinion at all. It was all about gekkogecko’s opinions, that he feels comfortable expressing them to gratuitously challenge the opinions of others, and that he presented them as being facts, when they are either demonstrably false, or unsubstantiated.

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Eudaimonia