It's all about omega-3 fatty acids and a woman's waist-to-hip ratio, or WHR -- a measurement that, according to an online calculator offered by Rush University Medical Center in Chicago, "looks at the proportion of body fat stored on your waist compared to that stored at your hips and buttocks."
...The lower the WHR, the better, according to the study by William Lassek of the University of Pittsburgh and Steven Gaulin of the University of California at Santa Barbara.
The study found that women who had a larger difference between their waist and hip measurements scored higher in tests than did those with "apple-shaped" bodies.
...They say that's because the fat on a woman's hips and thighs contains omega-3 fatty acids, which help in "critical brain-building" - and the curvier the hips, the higher the level.
The fat around the waist has higher qualities of omega-6 fatty acids, less helpful to brain growth.
"Shapely hips and thighs hold essential nutrients that nurse brains and could produce smart kids, too," Gaulin told London's Telegraph.