http://www.ehow.com/info_8292264_major- ... point.html
Motherhood The Greek philosopher Aristotle said that every ideal form can only be imagined with its function in mind, and it is impossible for an object to exist without a definite relation to its function. Therefore, the female body was the ideal form for its primary function, motherhood, even if it was considered inferior to the male ideal form. Gannon University's Sarah Lynn Andrews says Greek female statues showed women as round and youthful, "a tapered waist connected high connical breasts and curvaceous thighs." This was the ideal female form, perfectly fashioned for the function of motherhood.
Sexualized Female Form Before the fourth century B.C, artwork of Greek women were always shown in clothing. But the ideal woman of motherhood gradually became an idealized sexual figure. The revolutionary sexualized female ideal was the nude Aphrodite of Melos, a sculpture dating from 323 to 331 B.C. and now on display at the Louvre.
Can you imagine the primary female function of motherhood being accepted as beautiful by modern feminism. It would never happen nor would men want it since it is far more fun to enjoy the sexualized female form rather than thinking of children.
IMO beauty would be an aspect of ideal human types in a more real world. Ideal images have replaced the appreciation for ideal types so beauty is really in the eye of the beholder's imagination. Deciding on size 6 or size 12 seems to depend upon advertising.