Bostonian, I'd still argue that such surveys and longitudinal studies are just not asking the right questions.
While it is certainly true that women are punished professionally for becoming parents (and really, for even possessing the potential, truth be told), they aren't the only ones that suffer from these cultural norms. Men who do choose to spend time with their children as caregivers are often punished MORE than if their female partners had done so.
It's an expectation for women-- but it's still virtually a taboo for men. That has distinct sequelae, all of which are evident in or at least consistent with every study I've ever seen regarding lifetime earning power, career advancement, gender disparity, and the rest:
a) women are paid less to begin with because they are seen as inherently UNRELIABLE/LESS PERMANENT than their male (and non-childbearing) colleagues,
b) when women are mothers, they are passed over for critical assignments because there is an assumption that they will not make such professional work a top priority (and the coincident assumption is that a male colleague WILL, which is equally invalid)
c) when women continue to make "male" choices even after becoming parents, they are often labeled fairly harshly by even professional colleagues, and this has a social cost that can spill over into judgements about professionalism, as well (she must be pretty heartless... might be capable of throwing ME under the bus, too, if she won't even stay home with a sick kid)
d) when MEN make "female" choices, they are branded (often permanently) as being uncompetitive or unprofessional. Not management material, maybe even not 'masculine' enough in a male-dominated field.
It's a very sad state of affairs, really.
The fact that this disproportionately impacts women at high level earning potential probably has to do with the fact that most high income women are in STEM occupations, which are male-dominated.
I'd venture to guess that the most severe impact to MEN is also in male-dominated professions-- which would include STEM, but also manual labor positions in the blue collar sector. Those are positions where masculinity is very important professionally.
