Somewhere in Germany is a baby Superman, born in Berlin with bulging arm and leg muscles. Not yet 5, he can hold seven-pound weights with arms extended, something many adults cannot do. He has muscles twice the size of other kids his age and half their body fat.
I think most of us here would agree that it takes more than strength to be a Superman.
You also need to be able to fly. Oh yeah, and you need at least two girlfriends with the initials "L.L."