I thought they finally figured out that what prevents many women from rising beyond a certain point in their careers is that they take a couple of years off, or more, to focus on the more important things in life:
http://www.fww.org/famnews/1204c.htm
The researchers found that women put the brakes on their careers after their first child, regardless of their career status, men tended to scale back only after they had achieved an "acceptable level of flexibility and autonomy in their careers."
A family friend of ours got her law degree, but hasn't worked as an attorney in years, preferring to raise a happy, healthy, whip-smart brood of four delightful kids.
I mean, would anyone want to spend time at work if they didn't have to, when they could be spending time raising and teaching joyful children instead?