For girls it's the waist to hip ratio, for guys it's the shoulder to hip ratio. Basically guys are most attractive (in a genetic/evolutionary way) with smaller hips than shoulders, to kind of resemble an upside-down triangle. This signifies fertility as does the small waist with broader hips on women.
Broad shoulders. Broad shoulders, broad shoulders, broad shoulders! They drive me crazy. They're like instant likeability points, even if I find the guy to be a jerk or unattractive. Especially when paired with narrow hips. Not too narrow, but narrower than the shoulders. Basically, a V-shape.
I like athletic bodies. Not totally buff. Muscular arms, chest, abs. It's really hot when shirts stretch over nice pecs.
I like average-athletic, a bit of a muscle but not a buff type, for me when hips look much smaller than shoulders is not appealing. But I bet If I like the guy than it definitely for his personality first so it
outshines little imperfections. Between, guys with a little bit of extra can also look very sweet and lovable.
I really like when guys are lean muscled. Kinda like Chace crawford. I don't like their shoulders too big or their hips and waist too small in comparison to their shoulders, but you know, muscled nicely.