Superman is the bedrock of the superhero genre. He's the grandaddy of American comics and one of the most beloved fictional icons in history. Jerry Siegel and Joe Schuster's creation is so iconic, in fact, that the Superman logo is one of the most recognisable symbols on Earth, and that's without the character being deified by the mainstream.
The Man of Steel's legacy is incomparable, truly - and while everyone is likely to have their own favourite version of the character, few, if any, comic book characters have undergone as many changes over the years as he. The Last Son of Krypton has been the subject of numerous retcons, re-jigs and reboots to the point that, today, it's quite possible everyone has something about him that they don't feel too clued up on.
Convoluted backstories are part and parcel of the comics medium but especially the superhero genre. Naturally this can lead some to question the very tenets of a given character, Batman being one, and his Metropolis-based ally being another.
With both characters pushing upwards of eighty years worth of material on and off the page, it's easy to understand why that's the case. That doesn't mean that the answers aren't out there though...