Tuesday, October 11, 2011

Good sex? Science serves up the secret
An expert's guide to the birds and the bees
BY TOM SPEARS, CANWEST NEWS SERVICE
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Evolution has done odd things to humans in the name of continuing the species. It makes us go through emotional agony, act like fools, and spend huge amounts of time, effort and money chasing after prospective partners. And even finding Mr. or Ms. Right doesn't end the comedy of errors.

Sharon Moalem, a Canadian physiologist with a specialty in neurogenetics and evolutionary medicine, now practising in New York, has chased down the reasons for all the sexual things humans do. In fact, the title could equally have been "Why Sex Works" rather than "How." After all, if, for the benefit of some visitor from another planet, you wrote down the things men and women do, the alien's first question might well be: "Why?"

"You want to know what the magic ingredient to a good sex life is? Understanding," Moalem writes.

His goal (Sharon is a man's name in this case) is to lead the reader through the current state of research on sex and its many facets: Why many women report increased enjoyment of orgasms during pregnancy; why babies of women with HIV are more often born without the infection; how birth control pills work; why sperm cells are tiny models of amazing biological efficiency; how important cranberries are. (Short answer on cranberries: Very. If you don't get this, ask a woman.)

The start may be a bit slow to some. Moalem doesn't lead off with the newest revelations. Instead, he goes through a sort of academic boot camp: Laying down the groundwork, breaking up any misconceptions the reader may have had through two chapters on human sexual machinery (one chapter on women, one on men). In particular, how the machines work, and what sometimes breaks down, or even breaks apart, literally. This is not all fun stuff.

So fine, you have a lecture from an authority on how body parts form, mature and work.

You might be pardoned for getting to the point where nitrogen oxide works as a vasodilator to make blood flow change in passionate moments and thinking: Is that it? A book on physiology?

Luckily, it is much more.

Sex is perhaps the oldest preoccupation for humans, but there has been a great deal of discovery about it in modern times. Those willing to give Moalem time to warm to the subject are in for some revelations. Much of it deals with the mysterious, subconscious features that have evolved in humans to persuade us to go forth and multiply. For example:

- Women behave differently during ovulation. In a psychology experiment, volunteers were asked to look through photos of women, and determine which of them were trying hardest to look attractive. The faces in the photos were blanked out; all they had to go on was clothing, jewelry, and body language. Yet the volunteers -- men and women alike -- consistently decided that the women trying to look attractive were the ones who in fact had been ovulating when the photos were shot.

Oh, and women are more likely to cheat on a partner when they're ovulating.

"It's almost as if women are looking to mate when they're ovulating, but (looking) for a mate when they're not," Moalem concludes.


So why should we want to know this? To understand how evolution plays with our brains and bodies, he argues. "What you want may not be entirely up to you. But what you do about it is."

- Smell is an area of research in the sex business. Scientists ask volunteers to sniff clothing worn by men or women, gay or straight, and tell which smells they find attractive. I'm skipping the methodology, but one fact that emerges from this is that the man or woman who smells attractive to us is often the one whose genes differ from our own.

This matters to our health. Small groups of people who mix the same genes over and over develop gene pools that lack robustness. Shuffling the genetic deck is essential to humans. It may be what sex is for, mainly. And it turns out that we tend not to like the smell of someone with genes that resemble our own. Our noses are waving a red flag saying: Keep away, for the sake of your babies' health; in particular, for the sake of their immune systems.

An exception: Your family members generally don't smell repulsive to you. They may even smell reassuring, pleasant, safe. But they don't smell attractive in a sexual way.

- Penises can break, though rarely. Penile fracture, it's called. Seems easy enough to diagnose: "There can be a loud cracking or popping sound, and serious pain." The doctor ran across his first case when a man tried to get excited with a vacuum cleaner that was, and this is not a metaphor, turned on. Had trouble urinating afterward, let alone getting excited.

- Orgasm in women seems to have more to do with the mind than the body. It's "not just an automatic bodily response to sexual stimulation," say the researchers. It's emotional, and as closely connected to a woman's feelings for her partner as to her body.

- Some forms of attraction cross all cultural barriers. A surprising one: The more symmetrical a face is, the more the people will be attracted to it. Which makes evolutionary sense, since symmetry in a face is often linked with good health, and choosing a healthy partner is good for survival of the species.

- And a shocker: Women can have fraternal (non-identical) twins by different fathers. A woman who releases two eggs cells at once, and has sex with two men, can find that the two egg cells are fertilizes by different men. Genetically, these kids are half-siblings.

"One paper suggested that one in 400 pairs of fraternal twins born to white married women in the United States may actually have different fathers," he notes.

- Other topics: Teledildonics allows a person to manipulate a distant partner's sex toy via the Internet. Women ejaculate too. Pubic lice become rare in countries where Brazilian-style waxing is in vogue. There's a reason for women to prefer dark men: They're less like to have sperm damage from UV light. Breast-feeding can act as birth control, but it's risky. One in five American high school girls don't know how HIV is transmitted.

Moalem is used to writing for general audiences, so don't let that PhD deter you. The tone here is mostly serious but simple, down-to-earth, as conversational as a good family doctor, even though the content is rigorously academic. Moalem is used to writing for general media, and appearing on TV. It shows; he is not flippant but highly readable.

This is still a book to make us uncomfortable at times. Sex is not a simple world, and politics is not the only field that sees strange bedfellows. Yet most of us have seldom had access to learning of this kind. If we think we know the latest details on sexually transmitted infections, or pheromones, or hormones, or subconscious desires and choices, we're most likely wrong.

In light of that, it could be time for a refresher course.


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