But he is an alien. We know he's an alien. It's all part of the Hebrew analogy. Sent by his father to our world to fight for truth, justice, and the American way.
Okay, for argument's sake, let's take Superman as being a mythic demi-god like Hercules. It's pretty much the same thing. He can't really mate with mortals because he'd kill them. He's strong enough to champion and go on fighting evil things. He's been to the afterlife and come back.
Not much of a difference, really.