By Susan Antilla

Guys, if you are between 18 and 50 and work in finance, do your country a favor: Get a handle on the potential economy-killer that's running through your veins, and have yourself tested.

We need to know if you're a carrier of toxic testosterone.

Not all of you are financial accidents waiting to happen. But some of you are operating at levels that require serious adult supervision.

We know how you hate pain, so let me assure you that it won't hurt. Just a simple saliva test, and we can tell if you are high-risk. I can even recommend a doctor.

OK, so he isn't a medical doctor, but he knows a thing or two about markets and the nasty way that over-the-top testosterone levels can get men behaving strangely.

"During the dot-com boom, I noticed people acting odd, manic, delusional," remembers John Coates, a senior research fellow in neuroscience and finance at the University of Cambridge. "I suspected there was a chemical involved in causing these traders to go bonkers."

It was a chemical that miraculously evaded the less-agitated smattering of women on Wall Street, the trading doctor says.

Coates, a former derivatives trader at Goldman Sachs, Merrill Lynch, and Deutsche Bank, rounded up 17 London traders and took twice-daily saliva samples from them for eight business days. In a study published last year, he reported that the higher the traders' testosterone levels were at the start of the day, the more money they made.

Profits are a good thing, of course, but Coates' research suggests that the testosterone high could set off the kind of feedback loop that "might be responsible for turning a bull market into a bubble." It works like this: You start the day with high testosterone levels. You win a trade. Your testosterone-producing machinery, gleeful at the win, cooks up more testosterone. You take more risk. It feels great - you are invincible. You win again. It feels even better. Then - whoops - you get overconfident. You take too much risk. You blow it.

Traders aren't the only men who threaten their net worth with puffed-up confidence. The swagger of individual male investors resulted in their performing significantly worse than women in a 2001 study of 35,000 investors by the University of California, Davis. Men in the study traded 45 percent more than women, reducing their net returns by 2.65 percentage points a year. Overtrading by women reduced returns by only 1.72 percentage points.

Up until the financial meltdown, most decision-makers on Wall Street had a fondness for aggressive "masters of the universe," though there might be a notable exception at one Stamford, Conn., hedge fund.

In a lawsuit filed against SAC Capital Advisors L.P. in 2007, trader-analyst Andrew Tong said he'd been sexually harassed by his boss, Ping Jiang, who allegedly sought to eliminate Tong's personality flaws by requiring him "to wear certain kinds of clothing at work," according to court documents. SAC vehemently denied the allegations, and a New York judge sent the case to private arbitration - but not before CNBC reported that Jiang made his employee take female hormones to tone down his aggression.

If the allegations were true, maybe this guy Jiang was on to something.

Less radical, and less likely to wreak havoc on the male endocrine system, is better gender balance in the financial industry and markets. We need to counter the geysers of overconfidence that can lead to dangerous risk-taking, says Jonah Lehrer, a neuroscientist and author of the recent book How We Decide. "Perhaps what that requires is a few less men in the boardroom," he said.

It's already happening. In Iceland, two women were put in charge of troubled, nationalized banks. In Norway, the law requires that 40 percent of the directors of public companies be women. Sylvia Ann Hewlett, president of the New York-based Center for Work-Life Policy, suggests the same mandate for American companies.

Michel Ferrary, a human-resources professor at Ceram, the French business school, calculated the percentages of women in management positions at publicly held French companies to see if gender made a difference in the crashing markets of 2008. Companies such as Hermes International, with 55 percent female management, outperformed a major market index last year, while others such as Credit Agricole, whose management is 16 percent female, underperformed.

In the next bubble, maybe the guy-heavy companies will do best. But wouldn't we all feel better if the highs were lower and the lows were higher? While we work on the problem, have some sympathy for your male friends in finance. It isn't easy getting mocked for making a mess of things with your flighty, out-of-control hormones.

Susan Antilla is a Bloomberg News columnist.