"was that companies with flexible work policies or maternity leave benefits were actually linked with a slower promotion of women into top ranks. The explanation: Such benefits can lead to a check-the-box mentality, in which companies think they've done enough to help women along."

Or how about the more likely (but less P.C.) explanation : taking more time off work leads to well... less opportunities at work. As it arguably should be (because meritocracy)

Is the alternative (artificially "correcting" pay gaps) really fair to other colleagues who worked their asses off ? I can understand the good intent but it's a slippery slope : is that also going to apply to men who decide to take time off for hobbies, or is it a female-only privilege btw ?