I've got another scenario. What if Clark had multiple personalities. One was Clark, one was Superman. And he didn't know he was both men. It would be like twins only in the same body. And of course Lois didn't know they were the same man either.
There is a story with this premise. IIRC Lois discovers that sleepwalking Clark=Superman and then has to convince him that he is ala Nightfall. Good story but I don’t have the name at hand.
What might also happen is that Alt-Lois ended up, or almost-started-out as Lois's twin sister because somebody thought it fun to dump her in the delivery room. This we could get all the fun stuff with two Loises, one who's slightly wrong/out-of-place/off, with the resolution of sending her home, too, in the end.
Going back to the original theme—what if it was Alt-Clark that almost-started-out as Clark’s twin? Suppose Tempus decides to dump Alt-Clark in Kansas right after Clark’s ship landed. Tempus gets a Clark-free zone and the Kents would find two babies, one in a spaceship built-for-one and another identical in every way outside the ship. Clark could be explained by the Cold War experiment/alien theory, but there wouldn’t be any reasonable explanation for Alt-Clark until Martha read about cloning in the late ‘70’s.
