The Donation Oscillation Season 12, Episode 15 -  Aired February 7, 2019

The Donation Oscillation

When Penny's father, Wyatt, comes to town, he reopens the debate over Penny not wanting kids and Leonard donating his sperm to Zack and Marissa.

Meanwhile, Howard decides to keep the reservation for the "vomit comet" he originally made for Raj's planned bachelor party. Raj invites Anu and wants to turn it into a couples' trip, but Howard doesn't think Bernadette would enjoy it.

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Guest Stars: Keith Carradine as Wyatt, Brian Thomas Smith as Zack, Rati Gupta as Anu, Lindsey Kraft as Marissa, Eric Nenniger as Neil

Writers: Bill Prady (Story), Jeremy Howe (Story), Adam Faberman (Story), Steve Holland (Teleplay), Dave Goetsch (Teleplay), Maria Ferrari (Teleplay)

Director: Mark Cendrowski

Available on iTunes

Episode Notes

  • The title refers to Leonard changing his mind about donating sperm to help Zack and Marissa have a baby.

Episode Quotes

Marissa: It's a little weird for us, too. I mean, instead of our baby looking like Zack, it's gonna look like Leonard.
Zack: Or Penny if it's a girl.
Penny: No, no, it's not gonna look- Sure.

Raj: Uh, if you still want to go, you can go to India and help my dad eat all the nonrefundable sushi.
Howard: Indian sushi? I need a change of underwear just thinking about that.

Zack: Well, Leonard, we were hoping you'd go in on Monday.
Leonard: Okay.
Marissa: And they say, for the best results, between now and then, you shouldn't have sex.
Zack: Sorry, bro, I know it seems impossible to go for five days without, but I believe in you.
Leonard: Five days? My record is 24 years.
Penny: Uh, I think that also means no flying solo.
Leonard: Oh. Then my record is 14 years.

Marissa: And, well, we're really hoping for a son. So just, like, keep that in mind when you're in there.
Zack: Yeah, just think, "Little boys, little boys."
Penny: Still just totally not weird.

Sheldon: Hello.
Leonard: Oh, hey, Sheldon. We're kind of in the middle of something.
Sheldon: Oh, I won't be a moment. I just need to grab a book off a high shelf, which I can do because I am both tall and smart.
Amy: Sheldon, come home! They don't want to have your baby!
Sheldon: I don't know what you're talking about. Oh-oh, dear, I think I got something in my eye. My piercing, blue eye.
Amy: Sheldon!
Sheldon: Fine. I've also never had a cavity and I don't have asthma.

News Stories

Title Date Posted
1215 'The Donation Oscillation' Press Release January 24, 2019

CBS has released the synopsis for the February 7 episode of The Big Bang Theory, "The Donation Oscillation".  Full story


As Zack and Marissa join Leonard and Penny in their apartment, they thank Leonard again for agreeing to help them to conceive. Leonard says they’re happy to help. When Penny asks what the next step is, Zack explains that they were hoping Leonard would go to the clinic on Monday, though it means Leonard must refrain from sex until then. When Sheldon comes over to collect a book, he makes a big deal about how he is able to grab a book off the high shelf because he is tall and smart. Amy rushes over to take Sheldon home, saying Zack and Marissa don’t want to have his baby.

In Howard and Bernadette’s kitchen, Raj reminds Howard this week would have been his wedding if he and Anu hadn’t decided to slow things down. Howard tells Raj about the bachelor’s weekend he had planned: a trip on NASA’s “Vomit Comet”. Raj says they can still go and make it a guys’ weekend.

In the university cafeteria, Sheldon asks Leonard if he would want him to tell him if he had food on his face. Leonard wipes his face, but Sheldon reveals this was a week ago. After Howard and Raj sit down, Howard talks to them about their guys’ weekend. Unfortunately, Sheldon isn’t interested in a “vomit comet” and Leonard is busy as Penny’s father comes to town. Raj suggests making it a couples’ weekend instead, but Howard doesn’t think it’s something Bernadette would like.

After Penny sees Leonard taking a tablet in the kitchen, he explains they’re multivitamins that Zack and Marissa wanted him to take. When Penny’s father knocks on the door, she warns Leonard not to bring up any baby stuff about not her not wanting one or him helping Zack have one. After Wyatt sits down, Penny offers him a beer. He says he’ll have one if she is, and why wouldn’t she if she’s not pregnant. Penny blurts out that Leonard is helping her ex-boyfriend Zack have a baby.

In Howard and Bernadette’s kitchen, he asks her if she’d be okay if he spent the weekend with Raj. After Howard explains it’s the bachelor party he had planned, Bernadette asks if it’s a guys’ weekend. Howard admits Sheldon and Leonard couldn’t make it, so Raj invited Anu and Howard asked Stuart. When Bernadette asks why he didn’t invite her, Howard argues he knows her and she wouldn’t want to float weightless in an aeroplane. After Bernadette claims Howard doesn’t want her to go, Howard says he wants her to go so long as she is going to have a good time and not ruin it for everyone else.

Back at Leonard and Penny’s, Leonard accuses her of throwing him under the bus and making her father mad at him. Wyatt wants to get it straight with Leonard: Penny doesn’t want to have his kid but her dumb ex-boyfriend does. Wyatt says in Nebraska that’s kind of strange and Penny accepts it’s strange here too, but says she supports her husband. Still, Penny tells her father if he feels differently, he should feel free to say so and make a scene. Leonard says Zack and Marissa can’t have kids on their own and they like that he’s smart and want that for their child. Wyatt understands, comparing Leonard to a prize stallion on the farm which he put out to stud.

When Leonard goes to his bedroom as Penny makes the bed, she asks him if he had fun with his new best buddy. Leonard points out it’s her fault her dad likes him. Changing tack, Penny says he was right about one thing, she married a stud. Penny says she feels bad about throwing him under the bus and wants to make it up to him. As they move onto the bed, Leonard says he can’t do that for the next three days. Penny decides to just go to sleep instead. When Penny undresses to reveal a sexy outfit, Leonard knows what she’s doing. As she climbs into bed, Penny keeps trying to flirt with Leonard as she reads a comic book.

As Howard drives Bernadette, Raj and Anu to the Vomit Comet, Raj thanks them for doing this. Anu says she’s glad Bernadette came as Howard made it sound like this wasn’t her sort of thing. Howard apologizes as Bernadette insists she likes going fast, mocking Howard for his slow driving. Anu admits she’s always wanted to do this as she’s an adrenaline junkie. Bernadette tries to paint herself as a thrill-seeker, mentioning how she jumps on the back of the grocery cart at the supermarket and rolls through the meat section.

After a sleepy Sheldon gets up and makes himself a bowl of cereal, he is surprised to find Leonard asleep on his couch. As Sheldon tells Amy that Leonard is asleep out there, he wakes up and apologizes for using his key to their apartment. He says he needed a place to crash as his wife kept trying to have sex with him. When Amy asks why he’s trying to avoid having sex, Leonard says he’s “saving” himself for the clinic on Monday. After Amy points out Penny might not be totally onboard with the plan, Sheldon asks Leonard if he’s willing to go through with this even though she has reservations. Leonard says if Penny has a problem, she should talk to him about it. Leonard says he respects that Penny doesn't want to have kids, so maybe this is his chance to leave a little part of him behind. Amy points out it won’t make him a dad as it’ll be their baby not his.

In the “Zero G” waiting room, the couples are handed the waivers ahead of the “most intense experience” of their life. Bernadette notices there’s a lot of pages in the legal disclaimer. Raj, Howard and Anu sign their waivers right away and head to the changing rooms. When Anu asks Bernadette if she wants to go get changed, Bernadette is hesitant. She says she’s got two babies at home and wonders what she’s doing there. After Anu wonders why she came, Bernadette admits it was just to prove to Howard he doesn’t know her as well as he thinks he does. When Anu suggests she just be honest, Bernadette agrees and tells her she owes her $3,000 for those plane tickets to India.

When Penny returns from a long run, Wyatt asks if she’s avoiding him. Wyatt suggests she’s mad at him and mad at Leonard, but really she’s just mad at herself. When Penny wonders why she would be mad at herself, Wyatt thinks she might regret this whole “no baby” plan she’s got. Penny thinks it’s crappy of him to try make her feel bad. When Wyatt asks if she does feel bad, Penny admits she feels like she’s letting everybody down. Wyatt says she could never disappoint him, even though her high school years were rough. Besides all that, Wyatt says being her dad is the best thing that ever happened to him. He doesn’t want her to miss out, but if this is what she really wants or doesn’t want, he tells Penny he’s on her side.

When Leonard returns home, he tells Wyatt they need to talk. Leonard wants him to back off; if Penny doesn’t have kids that’s between them and he needs to stay out of it. Penny says that’s okay, she and her father already talked and they’re good. Leonard tells Penny he decided not to go through with this Zack and Marissa thing. He says he was fooling himself, he would have been heartbroken if he had a kid out there and he wasn’t his dad.

Back at the “Zero G” center, everybody is suited up and about to head out onto the tarmac. Bernadette tells Howard she doesn’t think she should do this. Bernadette argues they have kids and it’s not smart for both of them to be put in danger. Howard says since he’s done this before and she really wants to go, he’ll stay there. Unless Bernadette doesn’t want to go and he was right all along. In the end, Bernadette takes the “Vomit Comet” and screams about how much she hates it. When Anu reminds her she did this to prove a stupid point to her husband, Bernadette thinks it was worth it.

When Leonard phones Zack to break the news that he can’t go through with his donation, Leonard says he knows someone who might be interested. Across the hall, Amy yells “No. Absolutely not.”, so Sheldon tells Zack his wife says he’s not allowed.