Think about it: a short girl with thick thighs and big baby eyes will be considered attractive, but her brother who will look similar will be considered "meh" or unattractive,

meanwhile a 6' 2" guy with blonde hair, blue eyes, and athletic build is a stud. His sister, a blonde, 5'10" and slender will also be considered very attractive as well.

before you say "sexual dimorphism": a small petite woman with a babyish face will be seen as attractive by many because "neoteny",

but so will be a tall athletic woman with chiseled features.

It looks like women always win. When it comes looks in men the general idea of handsomeness seems to be much more narrowly confined to: tall, broad shoulders, square jaw.