An study came out a while ago, unfortunately I don’t remember where, that gathered men’s sweat and had women smell it (I think without telling them what it was). The women described some sweat as disgusting, and actually liked some odors so much they requested to smell them again at the conclusion of the smell test. It was determined that the more different the genetic strengths of the two people- I don’t remember how this was measured, I assume MHC- the better the woman thought the man’s sweat smelled.

I wish I could point you toward the specific study, but I do strongly remember reading about it several years ago.