The No. 1 impediment to women succeeding in the workforce is now in the home.

Women don't take enough risks. Men are just 'foot on the gas pedal.' We're not going to close the achievement gap until we close the ambition gap.

We know when we use the full talents of our population we're more productive. And we know that when people really feel like they can have flexible lives, they're better employees.

I spent most of my career, including my time at McKinsey, never acknowledging that I was a woman. And, you know, fast forward - I'm 43 now - fitting in is not helping us.

I gave a talk on gender stuff at Facebook one morning and a man didn't come. It was optional; he didn't have to come. But he sent a note saying, "I missed your meeting because I drove my kids to school so my wife could do something else. Thank you for making that possible." I think that employee is a loyal employee for Facebook and I think more companies should want that kind of loyalty.

Success for me is that if my son chooses to be a stay-at-home parent, he is cheered on for that decision. And if my daughter chooses to work outside the home and is successful, she is cheered on and supported.

What I tell everyone, and I really do for myself is, I have a long-run dream, which is I want to work on stuff that I think matters.