Final question: Why are Europeans diverse for hair and eye color but not for skin color? The reason may be a pre-existing sex difference that oriented sexual selection in one direction. In all human populations, girls become lighter-skinned during adolescence, with the result that young women are noticeably fairer than young men. A fair complexion was traditionally valued in women, who would make themselves even fairer by avoiding the sun, by wearing protective clothing, and by using face powders. This gender norm has existed across all cultures with one exception, albeit a big one: the tanning craze of Western women since the early 20th century. Thus, at least in premodern times, fairer women were preferred, and such a preference, under intense sexual selection, would eventually drain the gene pool of alleles for dark skin. This may explain the strange albino-like skin of Europeans.
