THAT conversation would go something like this, I imagine:
Selina: Well, I don't know about you, dear, but I had a LOVELY time today, didn't you?
Clark: *grunts*
Selina: Kon and Connor had such a lovely time, and that Mia is such a nice girl. *to self* Self-righteous little missy that she is.
Clark: *growls*
Selina: I do believe Kon may have found himself a girlfriend...
Clark: The scion of that flea-bitten rabble-rouser?! NEVER!
Selina: Oh, honestly, I know you don't like the man...
Clark: Don't LIKE? The man's a...
Selina: BUT that doesn't mean you have to hate his kids. I mean, they can't help their father, can they?
Clark: *seethes*
Selina: I thought little Lian was awfully sweet, didn't you?
Clark: She's not Ollie's, is she?
Selina: *sighs* No.
Clark: She's adorable, then. *warming up a bit* I remember when I was serving the sausages and she came up and asked for one, but she couldn't pronounce it properly - it was 'thothajith'. Heh.
Selina: Clark?
Clark: Mmm?
Selina: Have you ever thought about having kids?
Clark: *does a double take* Kids? Us?
Selina: Why not? We both LIKE kids...
Clark: Selina, I don't think you quite realize what you're asking here.
Selina: What's the problem? Don't you want to hear the patter of little feet?
Clark: 'The patter of little...' Selina, it's a little more complicated than that, I'm afraid.
Selina: *pouts* Oh, Clarkie. Aren't you overreacting just a teensy bit?
Clark: Selina, first off, I'm not human, remember? I don't even know if I CAN have children.
Selina: Of course you can! What about Kon?
Clark: Well - YEAH, but he's, you know - created in a lab out of bits and pieces of my DNA and... other peoples'. He's a test-tube baby.
Selina: OK, but we could always give it a try, couldn't we?
Clark: Selina, you might DIE! This baby would be half-me, remember? What happens if he kicks in the womb?
Selina: Come now, Clark, it took you years to absorb enough sunlight to...
Clark: ME, yes, but I'm a pure Kryptonian - I don't know how a half-breed would react. Anyway, do you really want to take the chance of having a hole kicked through your belly?
Selina: *winces* Well, OK, that does sound rather painful...
Clark: YOU might die, the baby might die - or you might be injured, or - oh, honey, it's just not worth it.
Selina: *pouts*
Clark: Besides, are you sure there aren't any ulterior motives here?
Selina: 'Ulterior'...? Why, whatEVER do you mean?
Clark: Don't play the innocent with me. You're telling me you never considered for a moment how useful a superpowered baby would be in a jewel heist?
Selina: *pretending to be shocked* Clarkie! You WOUND me! I would NEVER do such a thing! *in an undertone* I mean, not that the thought of playing Fagin to an extraterrestrial rugrat doesn't have its charms, but...
Clark: Mm-hmm. I can picture the security guards now. 'Say, Biff, did you just see a woman dressed as a cat clinging to a flying baby pass by that window headed for the penthouse?' 'You been drinkin', Bill?' You'd make millions.
Selina: *getting angry* Now that is just unfair! How DARE you accuse me of using a baby like that?
Clark: Oh, honey - honey, c'mon, I'm sorry. Look, how about this - how about we, uh, we offer to babysit Lian the next time Roy's busy, huh? That'd be nice, wouldn't it? It'd be ALMOST like having kids.
Selina: Well, I suppose... *brightens* And then maybe we could adopt!
Clark: *tugs at collar* One thing at a time, please. *to self* This can't possibly turn out well.