As almost anyone who has followed the exploits of Bill Clinton or Pee Wee Herman knows, humans will place themselves at tremendous peril to satisfy themselves sexually. From an evolutionary standpoint, this makes sense.
To pass our genes on to the next generation, we must engage in an activity that puts us at risk for disease and injury. Natural selection has endowed us with a hormonal system that sends us urgent psychological messages to have sex.
It has also created considerable redundancy in how we receive sexual cues, making it hard for any single mechanism to shut down our libidos. “This is a very complex system, where the complexity is part of its evolution,” says Kim Wallen, an
Because it is intricate, there is much about sexuality that we don’t know, and we have few answers for many practical health questions.
Why do people have unprotected intercourse, knowing they could become infected with a lethal virus? Why does female dysfunction remain resistant to treatments like Viagra? Trying to untangle these questions has required sophisticated research tools, and over the past decade a two-tiered approach has emerged.
The first involves probing the brain to understand the nature of sexuality. At
The male participants responded predictably: Heterosexuals were aroused when they watched women having sex with women; gay men responded to watching men having sex with men. But women had a different reaction: All the film clips aroused them equally. “Their sexual arousal doesn’t seem to map onto their stated sexual preference,” says Chivers, who is now a fellow at
The implications of the Northwestern studies are enormous. For one, they start to explain why Viagra doesn’t work for women, even though it stimulates blood flow to the genitals: The relationship between physiological arousal and sexual function is complicated. The results also offer important information to psychotherapists whose clients are struggling with sexual issues. “Because we have a male model of sexuality, women who don’t fit that model feel they’re different or weird,” says
The new findings may help clinicians whose female patients are confused by their erotic reactions to the “wrong” sex, for example. The other research tier involves looking at networks of people rather than individuals. “Nothing occurs in a vacuum,” says Alan Leshner, head of the American Association for the Advancement of Science.
“The more we learn about the context of risky behavior, the more we can develop strategies for dealing with its consequences.” Epidemiologists now talk about syndemics—sets of interlocking afflictions (such as AIDS, violence, and substance abuse) that affect entire communities. By studying the social forces that bind these ills together, “you can really push the boundaries of public health,” says Dale Stratford, a medical anthropologist at the Centers for Disease Control and Prevention in
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