In a previous post it was noted that physically attractive parents tend to have more daughters than sons. An article in Timesonline.com (via aldaily.com) clarifies and draws out the inevitable conclusion that follows from that fact. Satoshi Kanazawa, an evolutionary psychologist at the London School of Economics, observes:
Physical attractiveness is a highly heritable trait, which disproportionately increases the reproductive success of daughters much more than that of sons. If more attractive parents have more daughters and if physical attractiveness is heritable, it logically follows that women over many generations gradually become more physically attractive on average than men.
The article cites the work of Markus Jokela, a researcher at the University of Helsinki, who found that “beautiful women have [16%] more children than their plainer counterparts and that a higher proportion of those children are female. Those daughters, once adult, also tend to be attractive and so repeat the pattern.” Thus, “Over generations, the scientists argue, this has led to women becoming steadily more aesthetically pleasing.”
As for men, “by contrast, good looks appear to count for little, with handsome men being no more successful than others in terms of numbers of children. This means there has been little pressure for men’s appearance to evolve.”