Women with high levels of testosterone tend to pursue riskier jobs, according to a new study. After measuring female business students' hormone levels, experimenters had them play a complicated computer game. Those with the most testosterone tended to make riskier tactical decisions as they played. After graduation, they were also more likely to choose risky careers in finance. Does testosterone also play a role in the number of women stepping forward to serve in the military or police or fire departments? Maybe. If so, we owe the hormone our thanks.