Raj: Well, I can't eat like a ten-year-old all the time.
Penny: You're dating somebody! Who is it?
Raj: What? What are you talking about?
Penny: You only watch what you eat when you're afraid you might have to take your shirt off.

Sheldon: Woman, you are playing with forces beyond your ken.
Penny: Yeah, well your Ken can kiss my Barbie.

Raj: [to Amy] If you were having Sheldon's baby, would you really want him in the room?
Penny: Yeah, if he's in the room when they're making the baby, I'll give you $10.

Penny: I mean, who even reads Scientific American?
Leonard: It's kind of a big deal.
Penny: If it's such a big deal, how come the biggest celebrity they could get for the cover is a molecule?

Bernadette: Still, I can't believe you can turn ordinary skin cells into functioning brain cells.
Amy: Well, I turned this one into a functioning boyfriend, so sky's the limit.

Raj: Maybe there are other things we have in common. Come dinner-time, do you enjoy eating food?

Sheldon: Yeah, I have to say, it is nice to share this experience with someone who's on the same journey. Although right now ours is testing off the charts while yours is floating around in its own waste.
Bernadette: Are you actually comparing my human baby to your brain in a bowl?
Sheldon: Well, I didn't make you waddle up four flights of stairs for the heck of it.
Bernadette: You do realize my baby has functioning organs and can recognize voices.
Sheldon: Yeah, but ours can recognize a specific data stream among background noise.
Bernadette: Mine has a fully developed immune system.
Sheldon: Ours doesn't need an immune system because it lives in a state-of-the-art German incubator.