There is research that suggests, however…
* priming people to remind them that they belong to a stereotyped group actually causes people to perform worse (stereotypically) -- this is called stereotype threat, lots available if you googles
* guilting people about their culture's bad behavior / their personal bad behavior actually causes them to dig in their heels, not to feel bad and then change (because feeling bad is an identity threat (irony)) -- the study I'm thinking of for this one took young Germans and primed them to think about the abuses perpetrated by nazis (before they were ever born) and then polled them on attitudes towards Jews and found that the people who were exposed to the priming were less sympathetic, not more; the researchers had reason to believe this was due to the emotional knee-jerk reaction to guilt
And on and on. The research suggests that the furor is probably paradoxically counter-productive.
Furthermore, people who speak about "women in x" presume to speak for everyone, but they sure don't speak for me or most of my female friends. But they are painting us with the same brush because we've got the same genitals. Bothersome.
As for pg's opinions about startup-women-with-young-kids, it fits well with his other writing (programmers aren't just programmers, they're hackers; hackers are artists; nerds are unpopular in high school because they're way too awesome, etc) which is all about reinforcing identity. And of course he runs a business which depends on extraordinary (I would say over-)involvement with, and (over-)commitment to work. He also says he won't work with people who won't or can't move, too -- a non-gendered but identical outcome based on "devotion," not body parts or reproductive status.