I dont know much about scientific studies, but it wouldseem to me that the sscent/symettry link may be do to the simple fact that people with desireable symmetry are usually more athletic and active than non-symmetrical ones. In other words, buff guys sweat more, and lazy guys eat doritos and watch TV. While I know of no conclusions, I would guess that more activity produces a cleaner sweat with a different scent.
I used to call girls that always tried to snag my attractive friends "breeders" because I knew that they subconsciously wanted a baby from the guy. And the guys whom were "snagged" always became whipped and never did anything with the crew anymore...
Kinda irritated me...maybe I missed the scent.