Andrew Lincoln, Sarah Wayne Callies

[Spoiler Warning: This story contains details from both Sunday's episode of The Walking Dead and the comics the AMC series is based on.]

As if Lori's life in the zombie-infested world of The Walking Dead wasn't already tumultuous, she got some surprising news that will change the dynamic of the survivors.

In Sunday's episode, Lori (Sarah Wayne Callies) discovered she's pregnant. But whose baby is it? Husband Rick (Andrew Lincoln), who was comatose at the start of the zombie apocalypse? His best friend Shane (Jon Bernthal), who began a torrid love affair with Lori believing Rick had died at the hospital? To find out, we turned to Walking Dead creator Robert Kirkman, who also dishes on the impending conflict with the Greene family and the return of Merle Dixon (Michael Rooker)!

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Lori is pregnant! How is she going to deal with this revelation?

Robert Kirkman: It's definitely a terrifying thing to consider in this world with the state of things, it's like going back to pioneer days and having to worry about how you're going to give birth and how you're going to survive the pregnancy. This is a very complicated process in modern times, it requires a lot of interaction with doctors and none of that stuff is available, so it's going to be terrifying for her.

The big question is whether the baby is Rick's or Shane's. How is that going to affect the dynamic among the three of them in particular?
Kirkman:
This is going to be a catalyst for Shane. Once he finds out about this, assuming he does find out about this, he's going to react pretty strongly to this. His whole reason for worrying about Lori and Carl (Chandler Riggs) is that they've become a surrogate family for them. If he believes this baby is going to be his, that's just going to solidify his state with this family. It's definitely going to throw a wrench in the whole love triangle thing that's going on.

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Is Lori's pregnancy what Jenner had whispered to Rick at the CDC in the Season 1 finale?
Kirkman:
[Laughs] I can't say. That remains to be seen. All I can say is that it'll definitely be revealed this season. We're getting close to the midpoint of the season, so the likelihood of it being in the first half is looking pretty slim.

Will Rick start to clue in to what's going on with the tension between Lori and Shane?
Kirkman:
Yeah, definitely. The thing is: We never want our main character to seem like he's stupid. That's not something we ever want to do. The audience has been aware of this affair since the very beginning of the show. Rick is a police officer, so I would suspect that he might start catching on to things sooner rather than later.

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The survivors and the Greene family seem to be heading toward conflict. What can you tell us about what's ahead for them?
Kirkman:
It's interesting to take note that if this show was told from the perspective of the Greene family, then Rick and all of survivors would pretty much be the villains ... Hershel (Scott Wilson), Otis (Pruitt Taylor Vince), Patricia (Jane McNeill) and Maggie (Lauren Cohan) were having a pretty OK time on the farm, and then this group came and Otis was killed and now there's this powder keg of crazy people living on the farm. Of course this is going to lead to conflict. We've now seen that Hershel is saying they're going to have to get off his farm once Carl is better, and now that we know Lori is pregnant, and Hershel is really the only guy who has any kind of medical expertise, they've definitely got a lot of incentive to forcibly stay on that farm. Things will get pretty interesting soon.

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Based on the promos for next week, Merle is finally returning. What can you tell us of what he's been up to?
Kirkman:
All I can really say about Merle's return is that it occurred to us in the writing of bringing Merle back that we never even saw Daryl Dixon and Merle Dixon interact in the first season. They were never in a scene together. Getting to see Norman Reedus and Michael Rooker actually interacting and playing off each other is going to be an enormous treat for the audience and it's something we've been dying to get to.

Are you looking forward to Merle's return? Whose baby is Lori really carrying? Hit the comments with your thoughts.

The Walking Dead airs Sundays at 9/8c on AMC.