I found a reference to your project and I'm hoping you might have come across some findings and evidence that could explain this phenomenon beyond the usual 'Women leave their careers to form families' and 'Women come back from that in Part Time, which is not seen as valid for higher level management'.
My theory is that women do take time out for their families and thus tend to be older by the time they reach the career step where higher management begins. Men at this step are 45+ women are 50+. In addition, it appears that 50+ women are often not taken seriously while men who are 45+ (or even 50+) are taken especially seriously. At least this is my observation in the Tech / IT Industry. I'd love to know, if this is true outside my observations and if it's true beyond the tech/IT industry and beyond Germany. Did you come across or generate any stats? Do you know any other researchers on this topic?
Thanks for your time,
Anne Stahl