When the whole fuzz about gender discrimination started, Microsoft and Google published numbers, claiming women got the same pay at the same positions as men. Knowing there's discrimination from personal experience/feeling, I theorized, that women are discriminated in a different way: they don't receive promotions.
Under otherwise similar circumstances having children does not feel to be enough to explain why of 100 women hired in tech on professional roles less are promoted to higher positions, than of 100 men. That trend is (at least anecdotally for me) observable even before people become parents.
This "Bamboo Ceiling" shows the same effect for another potentially discriminated group of people.
https://youtu.be/eieVE-xFXuo?t=2m50s
He also makes the argument that the issue isn't why there aren't more women in these jobs, but why are there so many men insane enough to spend 80 hrs a week doing them? Money != Happiness.