Well, the answer seems to be "Society," since the ideals have changed with the times and conditions. In the past, women with large waists have been favored, for example. Sometimes it can indicate a woman who is better nourished and will yield healthier offspring.
(Denny Crane: "I Don't Want To Socialize With A Pinko Liberal Democrat Commie. Say What You Like About Republicans. We Stick To Our Convictions. Even When We Know We're Dead Wrong.")