> I know of one incredibly talented potential female founder who applied with a killer idea and was rejected.

I know of dozens of incredibly talented potential male founders who applied with killer ideas and were rejected. Seriously.

> I think it is very likely that YC has a strong bias towards men, which this data certainly supports.

Why do you think it's very likely? What data supports that. As one of the other commentators already pointed out, the percentage of YC founders that are women is about equal to the percentage that apply. Saying that the "data support" the argument that YC is biased when there is such an obvious alternative explanation (namely, that there are less female founders) is disingenuous.

> since YC is a for profit business they are making economically sound decisions.

Wait, what? Are you saying that since Silicon Valley (I'm guessing you mean investors in this context?) favors men, YC intentionally (and consciously) chooses to fund men in order to increase the chances that YC founders raise subsequent rounds of financing? That's crazy talk...

> saying any fault lies with women is really unfair.

I don't think anybody is "faulting" women. They are just stating the facts - there are less female engineers, and less female YC applicants.

Egads. Do you know how many applications YC gets every batch? The last publicly reported number was something like 400, and that was years ago. I'm sure is dramatically higher than that now. The competition is insanely high, and the vast majority of insanely talented people with killer ideas get rejected.

Also, a "killer idea" isn't what YC looks for. They look for good teams.

I wasn't suggesting that any of the women I suggested should apply to YC would have necessarily gotten in (none of the men I've recommended to YC have, so far). Odds are simply against it, but I think people should do it anyway, if they want to start a company that fits the YC model. My point was that of the people I've encouraged to start businesses, only the men have actually done so. The women always have too many good reasons not to. Their job pays too well, they like the food at Google too much and don't like to cook, they don't want to move away from their friends to live in the valley, they don't want to give up the security they currently enjoy for something uncertain, they don't want to give up their weekends, etc. There's always good reasons to take the safe path...men just seem to be more willing to ignore all those reasons and start a company anyway. Not all men or women fit this description, of course...free will seems to exist, and humans are widely variable. But, it's true enough of the time that I'm absolutely confident YC is not exhibiting a preference for male founders, and that the percentage of accepted female founders is reflective of the percentage of female applicants.

They've said in the past that the percentage of applicants who are women is the same as the percentage among accepted founders. Any bias therefore must happen at the self-selecting stage unless the female applicants are objectively better on average.

If you assume that the YC partners aren't biased (do you have any evidence otherwise?) this implies the self-selection isn't based on capability. (i.e. women seem equally confident to apply as men with the same abilities) Which pretty much just leaves us with the usual statistic of the percentage of women working in tech being low.

"I know of one [...] . I think it is very likely that YC has a strong bias [...]" is an interesting way to construct an argument. :)