[Helm]

punkgrrrlie10,as far as I can tell, what is considered the 'norm' in apperances is often a combination of parameters, among them current cultural trends and whatnot, but most prominent of which is the relation of one's body parts to each other. Partly speculation I guess, but it's said that the human body is composed of a series of golden ratio's. The ideal size of say, the front teeth and the ones next to them is smaller by the ratio 1 : 0.68. Same goes for eyes/nose, lower/upper arm and so on. The human brain is hardwired to relate such symmetry with beauty,which in turn one of the basic criteria when choosing a mate. So I guess what would be considered a safe norm when it comes to asses is their relation to the width of ones shoulders. Simple application of said ratio would provide some rough estimation.

However, culture, as said, stands to create small superficial alterations to this instinctual code (see current fashion model of beauty, or say the type of physique favoured in aboriginal tribes), but still, it's pretty much trustworthy.