Another reason for my lack of outrage is that I genuinely don't know in which direction this would be sexist.
Claiming that biological differences could result in different performance in the real world is usually enough to demonstrate sexism. But that's exactly what's claimed here, it's just that women would do better, which is ok. The article also implies that women are generally better ethically too which, which I think is pretty much coventional wisdom in the kind of circles I move in (I'm including TV and movies etc).
It may be that women perceive and act on risk in subtly different ways; that they don't, as a general rule, embrace the kind of massively aggressive behavior that brought us a Dow of 14,000 and then, seemingly overnight, a crash of epic proportions. Whether it be from a protectiveness born of biology or a reticence imposed by social norms, women may be less inclined than men to place the kind of bets that can get them in real trouble.
Conversely, women may also be more inclined to blow the whistle on others' risky business...
One possibility, explored in a fascinating study published last year by John Coates and Joe Herbert of Cambridge University, is that women simply don't have the testosterone for it; on the trading floor, they deduced, higher profits literally correlate with higher levels of the male hormone. Another, examined in laboratory experiments conducted by Muriel Niederle and Lise Vesterlund at the University of Pittsburgh, is that women are far less inclined than men to bet their pay on performance, even if they have evidence to suggest that they are superior performers.
The article doesn't say anything about IQ which is what really gets the blood flowing, but I'm not really sure why this is better.