Finally, more scientists are taking aim at the ludicrous idea that there is a biology of beauty—specifically, that men prefer women with an hourglass shape because that is a sign of fertility, and men wired to find fertile women attractive were and are more likely to have descendants, who would carry their gene for that preference. Or so the story has gone.

NEWSWEEK has not been immune to this claptrap, writing a cover story on the “biology of beauty” in 1996. In it, an anthropologist argued that “a larger proportion of a woman’s mate value can be detected from visual cues,” to which NEWSWEEK added that “mounting evidence suggests there is no better cue than the relative contours of her waist and hips,” with a waist-to-hip ratio of 0.7 (that works out to measurements of 36-25-36) being the reproductive ideal, and “even a slight increase in waist size relative to hip size [likely to] signal reproductive problems.” I can't imagine how many impressionable young women we sent scurrying for measuring tape . . . followed by an eating disorder.

But while a small number of studies indeed claimed that deviating from the “ideal” means a woman is likely to be less fertile, many others found no such thing. Camp out at an obstetrician’s and you’ll see that women of all shapes (not just Barbie’s) become pregnant. Or check out an IVF clinic, where hourglass figures arrive regularly because they can’t conceive. In his book “Adapting Minds,” David Buller of Northern Illinois University eviscerates the claim that men have evolved a preference for women with an hourglass shape: "it is anything but clear that there is a universal [male] preference for a 0.70 waist-to-hip ratio,” he writes. The study that made that initial claim failed to rule out the possibility that the preference was not innate at all but, rather, the product of exposure to mass culture and the messages it sends us about what’s beautiful. In fact, studies of isolated populations in Peru and Tanzania find that men there find hourglass women sick-looking. They prefer 0.9’s—heavier women.

This all comes rushing back to me because of a new study in the December issue of the journal Current Anthropology (the journal’s Website is only up to October, but keep checking back). In it, anthropologist Elizabeth Cashdan of the University of Utah argues that a factor that makes women stronger, more competitive and better able to deal with stress—all of which are good for health and staying alive, a prerequisite for having children—also tends to redistribute fat from hips to waist. The fat-redistributing compound is the hormone testosterone and its cousins, collectively known as androgens.

Cashdan’s work addresses what has long been a huge flaw in the biology-of-beauty claims, namely that few women in any society (Victoria’s Secret models do not constitute a “society”) have that 0.7 ratio. They tend to be much higher, with a cylindrical rather than hourglass shape. Surely, given that evolution cares only about whether your traits enable you to leave offspring, there would have been tremendous selection pressure for women to have an hourglass shape if it truly conferred greater fertility. So what explains all these imperfect women? (In Cashdan’s data from 33 non-Western and four European populations, the average waist-to-hip ratio is above 0.8.)

The explanation is that androgens increase fat around the waist, raising that ratio. But androgens also increase strength, stamina, and competitiveness. “The hormonal profile associated with high [waist-to-hip ratio] . . . may favor success in resource competition, particularly under stressful circumstances,” writes Cashdan. “The androgenic effects—stamina, initiative, risk-proneness, assertiveness, dominance—should be particularly useful where a woman must depend on her own resources to support herself and her family.”

She goes further: men may prefer this non-hourglass shape, despite claims to the contrary, in countries where women tend to be economically independent (Britain and Denmark). Only in countries where women are economically dependent on men (such as Japan, Greece and Portugal) do men prefer the thin-waist ideal of female beauty. In some non-Western societies where women bear the responsibility for finding food, men prefer larger waist-to-hip ratios. Cashdan puts it this way: “Whether men prefer a [ratio] associated with lower or higher androgen/estrogen ratios . . . should depend on the degree to which they want their mates to be strong, tough, economically successful and politically competitive.”