I'm white, but I do think that for the most part blacks do have better genetics than whites...Just look at pro sports.
I have to say, I think there are many blacks who have better genetics for getting big than whites do, but I think people have an inflated opinion of that.
I've heard people say 'black guys only pick up a weight and grow big over night', but I think that generalization is exaggerated. Most blacks who live here, where I live (Germany) aren't any more muscular than whites, really. Actually, the only guy for who thats true, that I know of is a friend of mine who's of mixed race. But were talking about the states anyways:
Outside pro sports, all black guys aren't really that muscular.
Take the rap industry for example..If I'm thinking of my favorite rappers of the top of my head, most of them never had a muscular physique:
all the members from the Wu-Tang clan (except for Ghostface Killah)
Warren G
Mr. Cheeks from the Lost Boyz
Pete Rock & C.L. Smooth (C.L. yeah maybe)
Eric B & Rakim
Masta Ace
2pac (yeah he was in good shape, but worked out a lot and was skinny in his early years).
I mean for every 50 cent you have multiple guys like outkast or snoop dog, jay-z or pharell williams...
I really think, there are more blacks who have superior genes for building muscle, but that the notion, that (almost) all blacks have an easier time building muscle might be a bit exaggerated.