We recently had the opportunity to chat with some young academic scientists. They love their work and their world, but it's very different from the professional trades and corporate worlds I've known. The differences may be most obvious to an ancient outsider like myself.
I was left with the dawning recognition that the debates about gender bias in science may, like most passionate debates, be talking around the elephant in the room. The baby elephant, that is.
That's not to exclude a direct bias against the XX chromosome, but even there I wonder if the bias isn't opportunistic. The modern life sciences have been brutally competitive for decades, and globalization is increasing that competition. Any opportunity to eliminate a rival may be used, and XX might come in handy.
Even so, what I read and hear suggests the direct bias is against distractions, and parenting is a major distraction -- especially for women. The productive lifespan of a scientist is as short as the major league baseball career, and it coincides with peak fertility periods. Competition is severe and resources are tight -- it's logical that parenting should be recognized as a fatal weakness.
If parenting could be outsourced completely I think science might accept that, but scientists are trained to be realists. They know mothers are prone to fall in love with their dependents, and thus to become distracted.
In this matter science seems to have rationally abandoned the pro-parenting bias that is common in other worlds, such as primary care medicine and even corporations. I work for a very typical large publicly traded company, and our divisional leader is a mother (though her children are grown of course). The distinction, I think, is that executive skills don't deteriorate as quickly as scientific skills. There's a potentially longer productive career, and there are a larger number of intermediate slots. A corporation will be "happy" to pay a "CEO-capable" mother a relative pittance to take a mid-level management position that's compatible with childcare. The most senior people of both genders, however, are not distracted by children. Their children are grown, or managed by a (female) spouse, or they are childless (often by choice).
If I'm right, and this may be a testable hypothesis, then the prospects for change are very limited. We would need to change the global competitive imperative, shift fertility into the 40s and 50s, or extend the lifespan of the brain to escape this emergent trap.