Stuart: Where are the kids?
Howard: I thought they were with you.
Stuart: What? No!
Howard: I'm kidding. They're at daycare.
Stuart: What about me makes you think my heart can handle that joke?

Leonard: Just tell me the truth, Mother. Was my whole childhood just one big experiment?
Beverly Hofstadter: Of course not, dear. It was thousands of small experiments.
Leonard: So that's all I was to you, a-a test subject?
Beverly Hofstadter: No, you were my baby and I found you fascinating.
Leonard: Really?
Beverly Hofstadter: Yes, watching you develop, tracking your progress. I know I'm not the warmest of parents, but it was time we spent together, and, honestly, those are some of my fondest memories.
Leonard: When did you stop?
Beverly Hofstadter: Oh, I can't tell you. The experiment isn't over.

Raj: I never thought I would see Sheldon enjoying himself around babies so much.
Amy: Yeah, how about that?
Raj: So he just happened to stumble upon a book about experimenting with them the same day we were hanging out with Howard's kids?
Amy: Yep, don't overthink it.

Raj: Where are the kids?
Amy: Oh, Sheldon's helping Howard give them a bath.
Raj: Hmm. So you really think you can trick Sheldon into liking babies?
Amy: I slept with him. I married him. You want to bet against me?

Sheldon: It's so funny, we did all these experiments on them and they didn't even notice.
Amy: I know, I was worried it would be obvious, but it wasn't.

Sheldon: You know, spending time with Michael and Halley today really made me think about our future children.
Amy: Huh, what an interesting and completely unforeseen development.

Howard: I think I'm capable of babysitting.
Bernadette: Don't call it babysitting; they're your children. It's called parenting.
Howard: What's the difference?
Bernadette: You don't get paid.

Bernadette: Remember, I'm leaving you with two babies. I expect to see two babies when I get back, and they better be the same two babies because I'll know.

Leonard: I love you.
Penny: I love you, too.
Leonard: And you're gonna do great. Just relax, stay out of your head, and try to enjoy it.
Penny: Aw. That reminds me of what I said to you the first time we slept together.
Leonard: I still use it. It's a mantra.

Sheldon: So, your convention is in San Diego, right?
Penny: Yes.
Sheldon: Great. I need you to settle a bet for Amy and me.
Amy: I say, when it's not Comic-Con, no one will be dressed as superheroes.
Sheldon: Mm-hmm. And I say fewer people will be dressed as superheroes but still some.
Amy: A crazy person in a cape doesn't count.
Leonard: Mm, why not? It counts at Comic-Con.

Sheldon: Also, if you get a chance to sneak into Hall H, last year, I left my neck pillow under my seat. Uh, third row, second from the aisle.
Penny: I'll see what I can do.
Sheldon: Thank you. At least there will be one superhero in San Diego.

Raj: So, Leonard, what are you gonna do while Penny's away?
Leonard: I don't know. Maybe watch a movie with subtitles.
Sheldon: If you're looking for something outside the norm, I have invented a new chess variant where the bishops can also move like knights.
Raj: What do you call that, Bishops Be Crazy?
Sheldon: First of all, it would be "Bishops Are Crazy."
Raj: Not if you're being crazy.
Leonard: Checkmate.

Howard: Hey. You guys want to come hang out at my place this weekend?
Raj: So we can help you babysit?
Howard: Uh, it's not babysitting. They're my children.
Leonard: They're not our children.
Howard: Oh. Well, for you guys, then, it is babysitting.

Sheldon: No offense, Howard, but I don't want to spend my weekend around your loud, sticky babies.
Howard: You can't insult my kids. I am offended.
Sheldon: No, you can't be. I said "no offense." That's like "no backsies" but for offense.

Bernadette: Oh, don't waste your time. His name is Danny. He works for one of the other drug companies.
Danny: Hey, nothing wrong with checking out the competition.
Bernadette: Aw, we don't see you as competition.
Danny: You should. Our anti-inflammatory is hitting the market this year, too.
Penny: Well, ours has zero drug interaction risk.
Danny: Yeah. So does an Altoid.
Bernadette: Speaking of Altoids, why don't you go get one?