I read this at my workplace recently in an article:
Work/life and family debate
From McKinsey April 2012 a Survey performed by Sylvia Ann Hewlett confirmed the higher women climb up the corporate ladder the fewer children they have whereas the reverse is true for men. In the 41 to 55 age range, 49% of the best paid women are childless. While only 19% of the best paid men in the same bracket are childless.
IMO - I think it's because women still bear the brunt of the housework and childcare which makes it much harder to focus and give our time to our careers.
Why do you think?
Note - I'm not a journalist and am a regular mumsnet poster 