[luchak]

Do you think there is some huge pool of people good enough for YC who just don't get in?

Yes, I believe that there are probably more than 300 people in the United States who could potentially be accepted to Y Combinator. I'd believe there are a lot more than 3000. We're talking about aptitude here, remember, so you have to consider people who could potentially get in, but don't apply. Do you really believe that the vast majority of the people who could even conceivably get in to YC, given some set of life choices, do in fact apply?

The only point I'm making is that small differences in underlying probability distributions can have large effects in the composition of people accepted into a highly selective program.

Yeah, if we're willing to grant you all kinds of crazy concessions, you can cobble together an explanation. But you're asking for a lot to make YC selective and sensitive enough for your example to be reasonable. The YC selection process has to be consistent and incredibly accurate. Most of the people who are even capable of getting in must apply. Acumen in various areas has to be minimally or negatively correlated, and to even be considered for YC, one person has to have all of the relevant skills.

And this is just to get close to the gender disparity that YC sees.

Sure, I agree that normal distributions with minor differences in variance are very different at the tails. But to get this to explain away the gender disparity in YC selectees? Epicycles on top of epicycles.

(Also: if this is really about the tails of the aptitude distribution, going by the paper you cited and your same arguments, we'd expect to see a lot more Asian women than Asian men in YC. I suspect this is not the case.)

If anything, I suspect your risk aversion point is closer to the mark, but that opens up an entirely new cultural and political can of worms.