There’s a lively discussion going in the comments over a Yglesias’ over a recent paper purporting to find that “women are less likely to take tenure track positions in science, but the gender gap is entirely explained by fertility decisions.” Replies Matt:

You say the gap is explained by “fertility decisions” I say it’s explained by “structural sexism.” Here, as in much of life, women and men are now allowed to compete on “equal” terms. The terms, however, were set up long ago — by men — before that was the case, operating under the implicit assumption that the competitors would be men who, if they had children, would have wives at home to take care of the children.

Especially in light of the debate that follows in the comments, I want to suggest disaggregating a couple of the distinct components of this. One question is whether there’s anything fundamentally unfair about a “parenting disadvantage.” In other words, if people who forego childbearing—and so have more time and energy to focus monomanically on their research—end up more likely to get tenure, is there anything wrong with that? More precisely, is there anything wrong with that in itself, leaving aside gender disparities, at least for the moment?

I’m inclined to see this one as a pretty easy “no”: There are lots of important and fulfilling things people want to devote their energy to other than work, childrearing among them, but it seems silly that in this one category we should pretend no tradeoffs exist between commitment to work and to other pursuits. If one person can put in 80 hour weeks and one person can’t, it seems weird to say it’s unjust to prefer the former just in the case when children are why the second person can’t.

But that question is, at least in principle, distinct from that of how this shakes out in terms of gender. Obviously there is a difference, since the study is finding parenthood to be a disadvantage only for women. Whether and to what extent this is an unfair difference will depend on the reasons for the difference. For instance, if university departments were just assuming that women who have kids will be bearing the primary responsibility for childrearing, while men will not, and making tenure decisions accordingly, that would be pretty clearly unfair, even if it happens to be statistically true. I’m inclined to say the same—though here join Matt in resting the blame with “society” rather than the university—if women disproportionately “choose” to stay home because of intense social pressure, or because sexism has granted their partners access to more lucrative jobs, biasing the economics of division of household labor.

But there are a range of other reason we can imagine where it’s less clear. What if one factor is just the physical incapacity associated with being the one to bear the child (and recover from bearing it)? In cases where the woman is choosing to be the one to spend more time home taking care of the child, does it matter to what extent her desire to do so is a function of systematic biological differences in parent-child bonding, of early socialization and internalization of stereotypes, or of plain old personal idiosyncrasies? Obviously the “internalized stereotype” account points to an element of potential unfairness in the early socialization of boys and girls, but once the preferences are there, I’m not sure to what extent we should regard outcome differences flowing from them down the line as cases of additional unfairness. Or, more to the point, I don’t know what the remedy could be, given that they are nevertheless now genuine preferences, beyond trying to change our educational policies for the next generation. (Raising the further thorny question what kinds of differences in socialization should be seen as inherently pernicious.) Least ambiguous seems to be the case where average levels of interest in hands-on childrearing just differ biologically across genders—here “fairness” doesn’t seem to enter into it at all, unless we want to consider “maternal instincts” as a kind of unlucky genetic disability for which society should compensate people.

I’ve belabored this a bit because, while probably almost nobody actually holds either extreme view, it seems as though the “sides” in debates over gender difference and fairness tend to get defined (perhaps mostly by their opponents) in terms of caricaturish poles: Either (1) We have at last triumphed utterly over a history marked by millennia of male dominance and marginalization of women, such that whatever differences remain are wholly attributable to evolutionary psychological differences, or (2) There are no important biologically-based differences other than the bits between our legs, and any differences observed are per se evidence of either direct discrimination or institutional sexism.

The problem, of course, is that both of these are so clearly false that almost nobody actually believes either one. Aggregate inequalities, depending on how and why they came about, need not also be inequities, but anyone who denies the persistence of real inequities is blind, stupid, or getting a paycheck. All of which is to say, these sector-by-sector inquiries into whether men and women are equally represented here or there don’t seem terribly fruitful if we’re not even making a pretense of knowing what the balance would be in an ideally fair world. In every case, you’re going to find a bunch of differences, and, with some exceptions, you’re going to find overt discrimination in hiring probably swamped by a bunch of other explanatory factors. The real action is going to be in evaluating the fairness of those factors, and I’m guessing they’re going to be similar ones across a variety of sectors. Doesn’t it make sense to focus more-or-less exclusively on these background factors, rather than variations in “representation” whose fairness is so hard to gauge in isolation?