Probably a man's values in general reflect in his preferences for physique. If he thinks that short people have no reason to live and wants his future sons to be on the basketball team, he'll value height. If he's prejudice against nerds, he'll prefer women with 20/20 eyesight or who wear contacts. If he values nature, he'll be attracted to women with natural hair color. As far as the size of her assets, my Freudian guess is it may be influenced by his mother's size.