Seems a silly (if not insulting) question. But in Descent of Man Darwin proposed a theory which, uncharacteristically, set women decisively apart from the rest of the animal kingdom.
According to Darwin, certain features (such as the beautiful plumage of peacocks) could not be accounted for by natural selection but were instead the product of sexual selection (i.e. aesthetic taste). Crucially, in the animal kingdom it was the female who acted as mate selector; Female birds, Darwin explained in a letter, “select the victorious or most beautiful cock”. (see the letter) Since female birds often selected their mates according to their plumage, so generation after generation male birds evolved with excessively extravagant plumage. Thus, according to Darwin, across the whole of the animal world – from birds to bees and everything in between – females were the driving force behind sexual selection.
There was, however, one important exception: human females. When it came to human courtship men chose their wives – of this Darwin was absolutely sure. “The members of our aristocracy,” he reported in Descent of Man, “… from having chosen during many generations from all classes the more beautiful women as their wives, have become handsomer, according to the European standard of beauty, than the middle classes; ”
The crucial question here, of course, is why was the story different for humans? Could it be that Darwin was inadvertently (maybe even consciously) reflecting the respectable values of Victorian society? It’s possible that this was an element of his thinking, but a book with so much frank discussion of human and animal sexuality would have already trespassed many boundaries of respectable literature.
We can never know for sure, but maybe Darwin’s uncharacteristic eagerness to separate the human and non-human worlds in Descent testifies the extent to which his scientific viewpoint was influenced by the patriarchal culture in which he lived? Perhaps the notion that human evolution was driven by feminine aesthetic taste and that males had evolved not for their brute force or intelligence but for their mere beauty was just one step too far for Victorian Britain?