Putting our sexuality to the testosterone test

One hazard of writing a column about sex is you learn things about yourself you weren't sure you wanted to know. It all started when I agreed to sample a test offered by Match.com as part of a new service known as chemistry.com aiming to measure compatibility.

A few of the questions looked like some sort of intelligence test. In one you had to determine the relative lengths of the horizontal and vertical pieces of a cross. In another you had to judge the relative sizes of two hexagons set against different backgrounds. The results on those came back immediately, and to my relief I got them right.

But what on earth did this have to do with dating and mating, I asked Rutgers anthropologist Helen Fisher, who designed some of the test. "That measures testosterone," she said. "I never can get those right."

In men, testosterone can be associated with sexiness as well as spatial ability, Fisher said. But what, I wondered, did high testosterone do for you if you happen to be a woman? I turned to Alan Booth, a professor of sociology at Pennsylvania State University.

From him I learned that women on average have about a fifth or sixth as much testosterone as a typical man. We secrete it from our adrenal glands. It's critical for sex drive, which is why scientists are experimenting with testosterone as a way to restore flagging female desire.

Can a couple of tests of spatial reasoning really indicate I've got more than a ladylike allotment of testosterone? Well, according to Booth, ability to judge spatial relationships does tend to reflect testosterone levels, which is why in general men do better on spatial ability tests than women.

"Males and females have had different roles for 10,000 years or more," he said. "Males needed to go on a big hunt ... . They needed spatial abilities that are very acute, for aiming an ax or a stone." Women, he said, needed to be nurturing and good at relationships.

That might have been, but even in the Stone Age there must have been women who didn't get a man or got a defective one. What if, in fits of frustration and protein craving, some of the more athletic types picked up axes or stones and felled their own animals? There's no reason such self-sufficient women wouldn't leave a genetic legacy, as long as they were decent hunters and slept around.

Over the last couple of years, scientists have discovered that your testosterone can fluctuate depending on your circumstances. For men, getting married causes testosterone to drop by about 20 percent, while getting hitched and becoming a father can make it dip 50 percent, said Peter Gray, an anthropologist at the University of Nevada.

Scientists first saw this effect in groups of Army and Air Force veterans. Last month Gray published a new study showing the same effect in Chinese men.

Higher isn't necessarily better, according to another study that showed low testosterone men make the best husbands - or at least they have the happiest relationships, especially when paired with low testosterone women.

Scientists know much less about why some women have more testosterone than others. Competition can make a difference, says Penn State's Booth. He and colleagues studied male and female rugby players and found for both sexes testosterone levels rose before an event but the women got a bigger hormone boost than the men.

A different study showed that women with high testosterone were less likely to get married or have children. But what's the cause and what's the effect there? Does having high testosterone make you want to stay single, or do the cutthroat demands of sports, the job market and parallel parking in the city spur some of us to make more male hormone?

Maybe Gloria Steinem hit on a biological truth when she noted, "some of us are becoming the men we always wanted to marry."

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(c) 2005, The Philadelphia Inquirer. Distributed by Knight Ridder/Tribune News Service.