From The Economist:
That the risk-taking end of the financial industry is dominated by men is unarguable. But does it discriminate against women merely because they are women? Well, it might. But a piece of research just published in the Proceedings of the National Academy of Sciences by Paola Sapienza of Northwestern University, near Chicago, suggests an alternative—that it is not a person’s sex, per se, that is the basis for discrimination, but the level of his or her testosterone. Besides being a sex hormone, testosterone also governs appetite for risk. Control for an individual’s testosterone levels and, at least in America, the perceived sexism vanishes.