The short answer is yes, absolutely. You may be primarily thinking of sex-linked dystrophies, such as Duchenne's or Becker's Muscular Dystrophy. The gene mutations for these types of dystrophy are...
Because they're a lot nicer to look at than a guy who's fat or just plain skinny..girls like guys who are strong (it's the whole, "carry me" thing).
ANSWER
The same reason some like them skinny,...