I'm not sure how to account for darker skin _may_ be less attractive to humans on a genetic level. It's a question science can't answer, so I don't know how we

I'm not sure how to account for darker skin _may_ be less attractive to humans on a genetic level. It's a question science can't answer, so I don't know how we could control for it. i.e, it could be the truth that the lighter your skin is the more attractive you are. How do we rule that out?