Why women keep getting prettier

It’s natural selection: better-looking people have more girls

by Rachel Mendleson on Monday, August 17, 2009 8:30am - 50 Comments

Why women keep getting prettierOn their 2006 album Boys and Girls in America, Brooklyn, N.Y.-based band the Hold Steady proclaim: “Guys go for looks, girls go for status”—an acute observation of a phenomenon, which, according to researchers, is having significant evolutionary repercussions. A new study shows that the importance that men, rather than women, place on beauty when choosing a mate is actually a form of natural selection. One result: women keep getting prettier, while men are as hairy and pudgy as they’ve ever been.

The University of Helsinki study is based on data collected in Wisconsin, which followed 10,000 high school graduates for four decades. Using the yearbook photos of a random sampling of 3,250 of the participants, researcher Markus Jokela asked a separate group of people to evaluate their attractiveness. On average, the women identified as attractive had 16 per cent more children than their plainer counterparts—a difference that was much less marked in men.

However, it’s not just the propensity of attractive women to have more kids that is pumping beautiful genes into the female pool. The fairer among us also tend to conceive more daughters than sons. In a government-backed study of 15,000 Americans, the most good-looking couples were 26 per cent less likely to have boys. Evolutionary psychologists Alan Miller and Satoshi Kanazawa explain this trend in in their 2007 book Why Beautiful People Have More Daughters. In part, the sex of a child is dependent, they argue, on the traits its parents have that are most beneficial to survival. And because being good-looking is a more significant factor in the reproductive success of women than men, it follows that pretty people would have more girls.

But while the recent findings might tempt men to settle into complacency about their looks, they would be wise to reconsider. Yet another study found that attractive women carry a hormone that makes them more likely to have affairs, and change partners if someone more desirable comes along.

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  • Cheri

    I agree! Of course I have three girls!

  • Pigsinspace

    I find it interesting that women who are prettier are more likely to have affairs or leave if a better mate comes along because of a HORMONE? Please!? How the hell can you determine that. This article is just another example of how we use science to justify and determine culture. It's like we need science to "tell us the story" of why things are the way they are. Science is just a meta-narrative. The data might be true, the the scientist herself/himself lives in a culture and uses that culture to interpret the data. Therefore the data reflects this contemporary moment. And to the jerk who made the comment about attending a feminist rally, all I can say is where, precisely are these "hardcore feminist rallies" to which you are referring? Just because someone believes in equal rights for all people (which is what feminism is) doesn't mean they hate men. We'll leave the hatred and oppression up to "dudes" like you – you have a history of doing it so well….

    • true north

      ''Ouch!!''

  • Zane

    Well yah, our definition of "pretty" changes over time. A few hundred years ago, plump women were more attractive because they resembled wealth and health rather than malnourishment. But women today still have the primordial instinct of being attracted to muscular guys for they are more likely to be a source of security rather than a weakling would. It's all about reproduction! Better stability and security = prosperity for the offspring of the species. However, there are other factors that come into play such as education and wealthiness which are not passed down through genetics. I wouldn't say that women are necessarily getting prettier, I'd say that the human race is. It's a big assumption but looking at what natural selection tells us, it's quite possible.

  • http://intensedebate.com/people/GeoffM GeoffM

    Eh…I'm no evolutionary biologist, but I'm pretty sure genes don't select themselves before a child is born–or even conceived. Stating that "the sex of a child is dependent…on the traits its parents have that are most beneficial to survival" is an extraordinary claim. By what mechanism is this selection occurring? If ugly boys are terminated in utero or gobbled up by family pets at a greater rate than pretty girls, that's natural selection. It ISN'T natural selection if individual traits (i.e. gender) never get tested in the environment.

  • Craig O

    There are some ways in which the genetic make-up of the sperm or egg can influence likelihood that that specific sperm or egg leads to conception or that the resulting zygote survives to birth. For example, sperm carrying a Y chromosome are more likely to fertalize the egg than their counterparts with an X chromosome – but male embryos are less likely to survive long enough to be born.

    Also, the mother's womb is an environment – natural selection can occur before birth, and often does.

    I somehow doubt that the attractiveness of women being passed along from mother to daughter matters in those circumstances, especially since the apparently unattractive fathers are contributing equally to their daughter's genetic makeup, but yeah, some genes do select themselves before a child is born or even conceived.

  • http://intensedebate.com/people/GeoffM GeoffM

    See? Now why couldn't the article say that?

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