>>/56367/
It "mostly" comes down to sexual selection (there is more to it, selfish gene stuff), but you are implying the existence of an inherent immutable pre-stablished universal sexually attractive genetic code, which we are only trying to approximate. That is not how it works.

What is sexually attractive is itself a mutable characteristic determinate partially by our genes, partially by social experiences. Being strong is only sexually attractive because it enhances chances of survival, which leads to more opportunities to have sex, not because of a recursive its attractive because its attractive because its attractive etc...