A friend posted a link to Facebook that showed two word clouds, one showing words used in advertising for toys aimed at boys, the other showing words used in advertising for toys aimed at girls. I'm not actually going to post the link here, because while I think the author's point is correct, I think the post itself does nothing to support the point being made, and this is all a distraction from what I actually wanted to talk about. There's been something I've wanted to say for quite some time about gender stereotypes, gender bias, and biology; and thinking about how some toys are perceived as gender-specific finally revealed to me what I think is the right way to say what I am trying to say, without coming across as patronizing.
Is gender discrepancy in toy preference purely a societal construction, or does it have any biological roots? Well, I don't think one can assert a clear answer to this question (it's undeniable that social convention reinforces this discrepancy, even if it didn't create it, which makes it very difficult to measure). But consider the following facts: Men are on average larger and more muscular than women. Babies only come out of vaginas, and milk (generally; don't distract from the central point) only comes out of the nipples of women. Given those realities, I don't think it would be surprising if we were to discover that, independent of culture, boys were more likely to play with fighting superhero toys, and girls were more likely to play with baby dolls. I'm not asserting that as true, but I really don't think it would be surprising.
But that's only a bit of speculation about what is; it says absolutely nothing about what we ought to do about it. Worse yet, it's not even the complete picture: It's undeniable that, even with gender stereotypes being bolstered by powerful cultural reinforcement as they are today, many boys would still rather play with dolls and many girls would still rather play with superheroes. It is not fair that these individuals be short-changed or stigmatized just because they don't fit a stereotypical mold, even if that mold has a perfectly natural origin. (Edit: In re-reading this, I think I inadvertently came across as presenting somewhat of a false dichotomy, i.e. that each individual either likes "boy's" toys or they like "girl's" toys. That's bullocks, and of course equally important is that even if, say, a given boy might usually want to play with superheroes, he should ideally not feel reservations about playing with baby dolls on occasions when it strikes him to do so.) Individuals should be empowered to do what they want, to act according to individual preferences and desires. This personal liberty and autonomy is one of our most important shared human values!
The upshot of this is that if it is the case that gender stereotypes have a biological basis (and again, I do not believe there is sufficient evidence to make an assertion about this either way), then that would only intensify the importance of minimizing any cultural reinforcement of those stereotypes. It might even suggest that we ought to work towards not only elimination of that cultural reinforcement, but an outright reversal of it, i.e. a society where it's "cool" to explore the opposite gender stereotype.
There is absolutely no reason to believe natural selection should be egalitarian in regards to gender. The moderate sexual dimorphism of our species suggests evolution has not been entirely blind to gender in H. sapiens (though thankfully we are quite a bit better off in that regard than C. lectularius!), and therefore we should be prepared that there might very well be natural behavioral differences between men and women. But as organisms with a uniquely powerful ability to reason about concepts of fairness and morality, we owe it to ourselves to do better than unguided evolution in this regard. The possibility that conventional gender roles might have biological roots is not an excuse to shrug our shoulders at stereotyping and inequality: rather, it is a call to redouble our efforts in combating those pernicious effects.