Here is another study on the effects of testosterone, after associations found with stingy behaviour, strong bones and teeth and male fertility and lower empathy.

New Scientist : Low testosterone linked with financial risk-taking

Quote Originally Posted by New Scientist
CONJURE up an image of a financial risk-taker, and you'll probably picture an aggressive Wall Street trader, testosterone surging as he closes the deal. But new research suggests that people with low levels of the male sex hormone are also likely to take financial risks.

Previous studies have linked high levels of testosterone to certain risk-seeking behaviours.
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Surprisingly, the biggest risks were taken by people with very high or very low testosterone, compared with the average levels for their gender