Originally Posted by groobie
Is there any canon regarding biological differences between Kryptonians and humans? (In L&C? In any other tv shows/movies/comics?)
In the novel 'The Death and Life of Superman', it describes Superman as having considerably more chromosomes than a human, to the point where the scientists are amazed that he looks so human.

"Oh, you can’t help that," said the Cat: "we’re all mad here. I’m mad. You’re mad."
"How do you know I’m mad?" said Alice.
"You must be," said the Cat, "or you wouldn’t have come here.”

- Lewis Carroll, Alice in Wonderland