@Antrim Honestly, if you want to understand why so many people think that the imbalance didn't just evolve naturally from choice, the best thing might be to find a few women you work with (or your best friend) and if they're willing to talk about it, really listen to what they have to say about their experiences.

Not everyone's encountered a terrifyingly huge amount of adversity, but a lot more women have than you'd think - and because it's something that's potentially present every step of the way, you really can't assume that women are making free, natural choices.

Also keep in mind that when people talk about sexism, they're not necessarily talking about conscious, malevolent bias. A lot of it is unconscious bias.

@Jefromi Everybody faces a lot of adversity.

@KarimL Absolutely. Doesn't mean it's the same experience for everyone. I don't think you'd say life is the same for rich people and poor people just because they both have troubles.

To me the problem seems to be the so called "leaky pipeline" such that a higher percentage of male graduate students go on to get tenure/full professorships than female graduate students. The differences in the number of graduate students is less concerning to me.