Zim had his head in Dib's lap. Not an irregular occurrence, but the words coming out of his mouth sure as hell were.

"There's some kind of parasite in my guts, but the computer said it was part human and tossed confetti on me? My smeet-parts are defunct as ever, so clearly the computer needs another-"

Dib nearly spit out his soda. "Smeet-parts?"

Zim blinked up at him, left antennae twitching. "Eh, didn't you find out on one of your x-rams that one time?"

"X-rays, and they're shit with tissue most of the time- you've got a womb?"

"Yes?" Zim seemed confused. "So? It's just part of the spooch like everything else, why does this matter? I didn't bug you about your kidney's beans."

"Zim, were you going to tell me this before or after we…?" Dib's cheeks flushed, and Zim stared at him before bursting into laughter.

"Oh, you think I'm- no, all irkens are created sterile! Even if we ever did do that , it's a mershpellid's chance on Blorch before there was a chance of-"

"Master, I've been trying to tell you for two days, you're definitely pregnant." The base computer's voice practically vibrated the walls, voice thick with irritation.

"Computer, stop trying to make jokes, they're terrible!" Zim called at it, even as Dib's face went white.

"Preg- how the fuck ? We've never gotten further than third base!" Sure, he'd known what Zim looked like naked now, but he'd just figured all irkens looked like that. It's not like he'd stripped Tak down when he was eleven, and he'd never seen any other irkens in in the flesh before. "You're not cheating on me, are you?"

"Who else would put up with him?" The computer chimed in. "No one's been here besides you two, Gir, and Minimoose. And your sister once, to threaten Zim if he hurt you in any particularly permanent ways."

"That was nice of her." Dib said numbly, still staring down at Zim.

"What, you actually believe the computer? It's been watching sitcoms with Gir FAR TOO OFTEN! It just wants drama." Zim glared at a random spot in the ceiling. "Zim would never fall prey to such primitive things as breeding."

"Zim…" Dib set a hand on Zim's waist moment before it was violently smacked off.

"I thought you were smart enough to believe me by now, Dib-fuzz!"

Dib quirked an eyebrow. "First, wow, that's the worst one yet. Second, seven years of knowing you say it's smarter to not believe you, and no amount of tonsil hockey will convince me otherwise. And third, your computer has never had a sense of humor that would drag out a joke for two days. Are you positive you're sterile?"

Zim blew his lips in a raspberry. "Pffft, of course. All Paks secrete hormones to keep it that way- can you imagine if the soldiers started mating willy-nilly with everything that had orifices to stick it in? Irkens are superior because the strongest of the genes are mixed together in variations programmed by the Control Brains themselves to keep us the best of the best!"

"Computer?" Dib looked up. "Anything else you've got to explain this?"

"Zim's messed with his Pak so much it probably disrupted those repression chemicals. He must have somehow taken in enough genetic material from you for his body to start working into assimilating it the old-fashioned way- mixing it in with the baby-maker." If the computer had a face, Dib was sure it would have smirked. "He does like biting, doesn't he?"

"Bah, that's nonsense."

"Zim, if that's what happened, this is a big deal." Dib tried to ignore the biting comment- it wasn't his fault that the computer was in every room in the base. "Babies are a big responsibility."

"Even if this was true, which it's not, irkens are perfectly self-sufficient moments after birth. They would need no responsibility from Zim." Zim bragged.

"That's only with Paks." The computer said flatly. "Human babies are absolutely useless, but so are smeets for the first few years. That's why they started smeeteries, to speed everything up."

"Well, any child of mine would be better than that, that's pathetic." Zim scoffed, before his brain caught up with his mouth. He slowly looked down at his chest. "Pak. Repeat the scan from earlier."

Dib watched as Zim's eyes clouded over, information darting across them and presumably directly into Zim's mind. He counted three beats before Zim practically ruptured his eardrums with a blood-curdling scream and dug his claws directly into Dib's arms.

"I'm what? "

A/N: So, Computer explained it a bit, but it's a one-two punch of Zim's futzing with his Pak messing up the sterilization hormones and Zim being given a body with a womb. I figure that's something that happens once in a while, Paks bond to 'wrong' bodies, but it's easy to just have the hormones adjusted. It's an accident on the part of the Smeetery, and it's in the meat-body, not the Pak. Besides there are few 'gender' differences between irkens, (mostly on the inside, lay two on a table and you'd never be able to tell the difference) so it's not even really considered part of Zim's 'defect'. This'll be mostly comedy, I think, with a dose of show-toned humor.

This was a lot of fun to write, and I'd really appreciate feedback!