Bernadette, Howard, Raj and Stuart are heading to the hospital while Bernadette has another contraction. Raj wants to drive like he's in India. Howard tells him to stop and tells Bernadette how much he loves her. Raj replies that he loves him too.Sheldon wakes up Amy just after midnight to wish her a "Happy Birthday". Amy is touched until Sheldon blows a birthday horn in her face. She takes the noisemaker and tells him that he can have it back in the morning. Sheldon hands her his birthday present and opens up her birthday gift, a framed functional MRI scan of his brain. She loves it. Sheldon points to the bright spot orbital-frontal cortex on the picture because he was thinking of her. Amy kisses him and then Sheldon asks if they are starting their annual coitus birthday festivities part of her the evening. Sheldon moves in on her while wearing his come-hither pajama bottoms. Penny knocks on the door announcing that Bernadette was heading to the hospital. Amy says they should stop. Sheldon agrees and says that due to childbirth and looming coitus, it was a banner night for female genitalia. Amy smiles at him.
Bernadette, Howard, Raj and Stuart make it to the hospital. Althea the nurse (from the pilot and other episodes) makes cracks asking about the three guys and one expectant mother whether this was some "Mamma Mia" nonsense. No Howard is the father though he doesn't know how far apart her contractions are. Raj does. Twelve minutes. The nurse wonders why they came so early. They also tell her that they don't know what the sex is of the baby though Raj knows. He tells his creepy story on why he knows. Althea sends them home until the the contractions are five minutes apart for about an hour. When Raj tries to over complicate the time of her contractions, the nurse suggests a home birth.Sheldon, Amy Leonard, and Penny are heading down the steps. Sheldon didn't want to look foolish if Howard started handing out cigars, so he had to find his bubble gum cigar. Leonard then forgot his inhaler. Penny gets a call that it's a false alarm. Amy sighs that first births can take a while. Sheldon then wants to reconsider the Flash onesie he bought. Amy wants to head back to their apartment, while Penny suggest that they go to a diner. Sheldon tells Amy that since its her birthday, she should decide. Now Penny gets excited and says that they should head to a bar. No. Leonard then states that they want to go have sex. Penny calls it their annual birthday booty spectacular as she sends them off to have fun. Leonard and Penny head off to get frisky with her wheezy sexy little man.
Back in their kitchen, Raj is filming a nervous set of soon-to-be-parents. Raj comments that she just wasn't ready to make the right entrance that Raj understands. Howard tells him to turn it off, while Raj is doing it for the baby. He says that someday she is going to see the film. Oops. Bernadette and Howard are disappointed that Raj let it slip that they are having a girl. Raj ruined the surprise and he also had already told Stuart.
Back in Shamy's bedroom, Amy asks where were they. Sheldon described and it as kissing like randy teenagers and that Amy's nose whistles. She apologized while Sheldon then called her a sexy little tea kettle. They try again and Sheldon thinks that it was being forced like all the "Pirates of the Caribbean" sequels. Amy realizes that the mood is different. Sheldon still wants to continue since Leonard and Penny are probably engaging and he doesn't want to disappoint them. Sheldon does want to continue since it is her birthday; however, Amy has a little surprise that might get them back on track. Sheldon thinks that it is something to do with trains. No.
Leonard comes out with his spare inhaler and ask Penny if they want to have sex. As they start to kiss, Raj knocks on the door. Raj got thrown out for telling them that the baby is a girl. Oops he did it again. Penny asks that if they are quiet, he might go away. Raj heard that.At Sheldon and Amy's apartment, Sheldon has his eyes closed as Amy comes out in a Harry Potter robe posing in the doorway. She thought that Harry Potter could make things hotter. Sheldon is impressed, Wowzers! She goes back to get him his robe. Sheldon calls her a naughty girl because wizards from different dorms will be sleeping together. Then he is a bit annoyed that she went to a Harry Potter Wizarding World theme park without him. She then asks if he wants to argue on her birthday. Sheldon doesn't want to and they start to kiss. There's a knock at the door. Amy sticks her head out the door and asks if this intrusion was about the about the baby. Raj replies that people keep kicking him out of places. Amy tells him to get used to it and slams the door. Then Penny and Leonard run out of 4A out yelling that they are all heading toward the hospital because Bernadette's water broke. Amy shouts that they have got to be kidding.
Howard and Bernadette head to the hospital with Stuart at the wheel. Howard thinks that Stuart is driving like an old man, while Stuart says that he can't see during night time. As another contraction hits Bernadette, she yells at him that the gas pedal is on the right.
Sheldon, Amy, Leonard, Penny, and Raj are in the car heading there themselves. Penny says that it's cool that the baby will be born on Amy's birthday, She complains that she thought the baby was supposed to ruin their sex life and not hers. Raj then complains that he should be there helping them out since he has been doing it for nine months. It only took Howard five minutes to conceive it which surprised Sheldon, but pleased Amy. They end up discussing the interruptions of the their sex lives and how long it took. Raj adds that they threw him out and let Stuart stay; Sheldon points out that he just discovered Amy went to a Harry Potter theme park without him, but he's not going to ruin her birthday because of that: instead he's just going to let it ruin a few individual hours every day for the next year and touches Amy's nose with a "BOOP!".
Howard helps Bernadette through another contraction. She wants some ice chips; however, Stuart finished them. He goes out to get some and Howard tells him to not come back. Howard and Bernadette discuss names. Howard wanted Wally Wolowitz if it was a boy. Bernadette suggests naming her after his mother, but she hated that name. Her middle name? Melvina. Howard really missed her and thinks that she would have been a great grandma.
The gang is waiting while Leonard cannot believe that Howard was going to be a father. Amy adds that Penny is the one who introduced Bernadette to Howard. Penny quips asking how many times does she have say that she is sorry. Then they all consider how far them have come since Penny moved in and that they all have a lot to be proud of. Raj gets mad that they all think he has done nothing. Stuart tries to console him and then Raj complains that he is as awesome as pasty-faced comic book store owner. Raj leaves and Leonard apologizes. Stuart is fine because he is in a hospital and is not the patient.Howard is now walking Bernadette around and telling her to remember what she learned in birthing class. Yelling she complains that she thought it was stupid and she was right. Raj peeks in, hears Bernadette's next rant that she wants to snap off her uterus. He nods and leaves.
Raj returns to the waiting room. Penny starts to tell Raj all the things he has accomplished like now being able to talk to females. Raj thinks sarcastically that now he can talk to them about breaking up with him. Stuart tells him that at least he can be a dog owner. Later Penny returns with two bags of M&M's. One of them was Raj's. Howard comes in and announces the birth of their daughter, Halley named after Halley's comet. Also like the comet, Bernadette is not having sex with him again for 75 years. Howard can't wait for They are all so happy for Halley to meet her aunts and uncles and Godfather (Raj). Raj is ecstatic that he has a dog and a godchild.
Peeking into the baby nursery, they see all the new individuals. Sheldon thinks that some will be successful and others will be homeless. They all wonder which one Halley is. All the babies look the same to Amy. Raj is sure he knows since it's his goddaughter. Then they hear one that cries like Debbie Wolowitz, and are weirded out, as Raj remarks, "That one."
Amy and Sheldon are returning from the Wizarding World Of Harry Potter dressed appropriately having had a fun day. Amy thinks that he would be tired. Sheldon replies, "I saw a magical train and reported a guy for cutting in line. If that's not foreplay. I don't know what is." They both race into their apartment for a romantic evening.
- Guest starring:
- Teleplay: Steven Molaro, Eric Kaplan and Tara Hernandez
- Story: Chuck Lorre, Steve Holland and Maria Ferrari
- Title Reference: Howard and Bernadette's baby girl Halley ends up with the same birthday as Amy.
- Taping date: November 22, 2016
- This episode was watched by 15.96 million people with a rating of 3.4 (adults 18-49).
- Total viewers including DVR users 21.26 million.
- The Big Bang Theory was ranked #1 for the week ending 18 December 2016.
- This episode aired in Canada on December 15, 2016.
- Chuck Lorre's vanity card 
- Caroline Preece of Den of Geek! - It’s a strong episode overall; even if there are zero surprises mixed in to keep things interesting. It’s the kind of episode older sitcoms tend to churn out when they get into double digits (see also: Friends), coasting on our collective affection for these people and familiarity with ongoing gags. That’s what the ‘twist’ at the end really is – a joke that only fans who’ve been watching the show for years would get. If this really is the beginning of the end (I’m aware I’ll look silly if it’s not), then I’m intrigued about what might be to come in 2017. 
- IMDb user reviews 
- Bernadette was pregnant at least ten months as she was already pregnant in "The Valentino Submergence" which was ten months before this episode on Valentine's Day.
- One year anniversary of Amy having sex and Sheldon "gives it to her" again.
- Bernadette gives birth to her baby, a girl named Halley.
- Howard and Bernadette's baby will share a birthday with Amy.
- The birth gets in the way of both Leonard and Penny and Sheldon and Amy having some intimate time together.
- Amy dresses in Harry Potter robes before she has birthday coitus with Sheldon. She wears Hufflepuff Robes, while she gives Sheldon Gryffindor robes.
- Halley has a voice only actress listed to portray her, Pamela Adlon.
- Vernee Watson as Althea has been playing a nurse on TBBT since the Pilot. This is her first appearance since "The Werewolf Transformation" (S5E18), a span of 113 episodes.
- Althea's full name is revealed to be Althea Davis.
- Howard's mother was revealed to have always had candy in her pockets, and her middle name was "Melvina".
- This episode also aired the same night as the release of the new Star Wars Anthology film, Rogue One: A Star Wars Story; however, unlike last year's episode "The Opening Night Excitation", which both referenced and tied-in the then newly released "Star Wars: The Force Awakens," this episode made no mention or reference to the movie at all; however, as Halley was born on December 15, she could be considered a "Star Wars" baby.
- Bernadette does not share any scenes with the Lenny and Shamy duos since they are in the waiting room.
- Halley has the same birthday as her "Aunt" Amy.
- Leonard says he has come to peace with his relationship with his parents, likely suggesting that there has been some improvement in his relationship with his mother and that he and his father have a closer relationship than before.
- This episode takes place on Amy's birthday, and since Amy's birthday is known for being December 17, that means this episode takes place on December 17, 2016 in their universe, 2 days after this episode aired on TV in real life.
- Howard says he was hoping to name their baby, if she was a boy, Wally Wolowitz. He still could've; Wally is a unisex name.
- Sheldon: Amy? Amy? Wake up.
- Amy: Wh…what’s wrong?
- Sheldon: It’s midnight. Happy Birthday.
- Amy: Sheldon.
- Sheldon: [Honks birthday horn.] Honk!
- Amy: [takes the horn] Okay, you can have this back in the morning.
- Sheldon: This is for you. I was going to wrap it, but touching Scotch tape gives me the heebie-jeebies.
- Amy: I’ll put that on the list with peaches and felt. What is it?
- Sheldon: A functional MRI of my brain. I did Sudoki before they took it so I’d be ripped.
- Amy: I love it. Thank you.
- Sheldon: And it’s not just an MRI. The frontal orbital cortex is lit up because I was thinking of you.
- Amy: [now touched] Sheldon. [they kiss]
- Sheldon: We seem to be moving on to the annual coitus portion of your birthday festivities.
- Amy: Is that okay?
- Sheldon: I didn’t put on my come-hither plaid PJs for nothing.
- Amy: You hate Scotch tape, but you love Scotch plaid. You are a mystery. [Romance starts.]
- Penny: [Knocking.] Guys, wake up. Bernadette’s having her baby.
- Leonard: Come on. We’re going to the hospital.
- Amy: I guess…I guess we should stop.
- Sheldon: Yeah, I’m afraid so. Child birth. Looming coitus? This is a banner night for female genetics. [Amy smiles.]
- Althea: Now I see three of you. Do we know the father, or is this some Mama Mia nonsense?
- Howard: I’m the father.
- Althea: Okay, Dad, how far apart are the contractions?
- Howard: No idea. Ask him. [gestures to Raj]
- Raj: Twelve minutes.
- Althea: Twelve minutes? Why are you here?
- Stuart: Aren’t we supposed to get here an hour and a half early?
- Althea: This is the hospital, not the airport.
- Bernadette: I’m sorry. It’s our first time.
- Althea: It’s okay. The little one will be here before you know it. Do you know what we’re having?
- Howard: No. we’re keeping it a surprise.
- Althea: Old school. Nice.
- Bernadette: Not that old school. He knows. [gestures to Raj]
- Raj: You see, I was at the doctor’s office and the folder was right there, so I took a peek…
- Howard: And talking like this doesn’t make it sound less creepy.
- Althea: Sweetheart, go home. Come back when the contractions are five minutes apart for an hour.
- Raj: That’s ambiguous. Is that five minutes apart starting at the top of the hour apart or is that five minutes with the first contraction so essentially like sixty-five minutes.
- Althea: [annoyed by Raj's technicality] I’m just throwing this out, but home births are very popular these days.
- Sheldon: Wolowitz might hand out cigars. I had to find my bubble gum cigar so I could join in without looking foolish.
- Amy: So…where were we?
- Sheldon: Well, I believe we were kissing like randy teenagers and your nose was whistling ever so slightly.
- Amy: I’m sorry.
- Sheldon: Oh, don’t be. You were like a foxy tea kettle.
- Amy: [Laughs] Well, shall we start over?
- Sheldon: Very well.
- Amy: What’s wrong.
- Sheldon: I’m not sure. Earlier tonight things began organically and now it’s being forced like all the “Pirates of the Caribbean” sequels .
- Amy: Okay, that makes sense. I mean, the mood’s a little different now. We-we don’t have to rush.
- Sheldon: Oh, okay, I know that Leonard and Penny think we’re doing it and I don’t want to disappoint them.
- Amy: And the mood continues to change.
- Sheldon: No, and also, I don’t want to disappoint you. I…You know, come on, it’s your birthday. I can soldier through this.
- Amy: Ho..hold it. I think I might have a little surprise that might get things back on track.
- Sheldon: Intriguing. Is “back on track” a hint that it has something to do with trains?
- Amy: No.
- Sheldon: Because if it did have to do with trains and you were gonna give…
- Amy: It’s not about trains!
- Sheldon: Oh, not even a cozy sleeper on the Orient Express?
- Amy: Stop talking about trains!
- Sheldon: Who’s killing the mood now?
- Sheldon: Can I look yet?
- Amy: One second. All right you can open your eyes. [Sheldon opens his eyes, and sees her in a Harry Potter Hufflepuff robe and scarf. holding a wand] I thought I’d let Harry Potter make things hotter. [Giggles]
- Sheldon: [entranced] Wowza.
- Amy: I got a Gryffindor robe for you.
- Sheldon: Oh… A Gryffindor sleeping with a Hufflepuff? How scandalous. You naughty girl. You went to the Wizarding World theme park without me.
- Amy: I did. Am I in trouble?
- Sheldon: Yes you’re in trouble…. You went to the Wizarding World without me.
- Amy: Wait. What just happened?
- Sheldon: You know. I’ve been planning to go.
- Amy: Sheldon, do you really want to argue with me on my birthday?
- Sheldon: Oh, you’re right. I’m sorry. [they kiss]
- Amy: Oh, Happy Birthday to me!
- Raj: [knocking] Hello…
- Amy: [answers the door.] Is this about the baby?
- Raj: No. People just keep kicking me out wherever I go.
- Amy: Good. Then you’re used to this. [shuts the door]
- Penny: [running out of 4A] Hey, Bernadette’s water broke!
- Leonard: Come on. Everybody to the hospital!
- Amy: You’ve got to be kidding me!
- Howard: Just try to relax. We’ll be there any minute. Stuart, stop driving like an old man. Speed up a little.
- Stuart: I’m not an old man! I just can’t see at night.
- Bernadette: [groaning in pain] Here comes another one. Hey, squinty! The gas pedal’s on the right!
- Stuart: All right, hang on. If you see any pedestrians, just call ‘em out.
- Raj: This is not how I pictured this day going; I should be with them right now.
- Penny: It's funny, Howard and Bernadette are having their baby on your birthday.
- Amy: Yeah, but I thought this baby was supposed to ruin their sex life, not mine.
- Raj: And the worst part is they kicked me out and let Stuart stay!
- Amy: I understand, but can you just let it go? This is a very special day for them.
- Sheldon: You know, I just found out Amy went to a Harry Potter theme park without me, but I'm not going to ruin her birthday. I'll just ruin 24 individual hours throughout the year. [touches Amy's nose] Boop!
- Howard: Deep breaths. Slow breaths.
- Bernadette: I’m so thirsty. Give me more ice chips.
- Stuart: [crunching] Sorry, I thought these were room ice chips. I’ll go get some more.
- Howard: Uh, Stuart. While you’re out there, don’t come back.
- Stuart: Okay.
- Howard: So, what are we gonna name this kid? Now that we know she’s a girl, it kind of ruins my plan for Wally Wolowitz.
- Bernadette: Could name her after your mom.
- Howard: Debbie? [chuckles] No. She hated that name.
- Bernadette: Did she have a middle name?
- Howard: Melvina?
- Bernadette: Let’s keep thinking.
- Howard: Hmm.
- Bernadette: Ah.
- Howard: It sucks that she’s not here.
- Bernadette: I know.
- Howard: Hmm. She would’ve been the best grandma.
- Bernadette: She did always have candy in her pocket.
- Howard: Yeah. I was twenty years old before I figured out Tootsie Rolls weren’t naturally warm.
- Bernadette: I didn’t know her five minutes and she asked, “Are you a Milky Way or a Snickers girl?”
- Howard: Thank God you answered right, we wouldn’t be here today.
- Howard: Come on, Bernie, breathe. Remember what you learned in birthing class.
- Bernadette: I remember thinking, “this is stupid” and I was right!
- Howard: Do you want me to get the nurse?
- Bernadette: No! If one more person puts their fingers near my uterus, I’m gonna cross my legs and snap ‘em off!
- Howard: She’s here. The baby’s here.
- Penny: Oh!
- Raj: Congratulations!
- Amy: How’s Bernadette?
- Howard: Tired, but great. They’re both great.
- Penny: Does the baby have a name yet?
- Howard: We have named her Halley.
- Penny: [almost gushing] Oh!
- Leonard: Like Halley’s comet!
- Howard: Exactly. Also like the comet, Bernadette said she’s not gonna have sex with me for another 75 years.
- Amy: [to Sheldon, hastily] That’s not a real thing, he’s just joking.
- Howard: I’m gonna get back. Thank you for staying up, I can’t wait for Halley to meet her new aunts and uncles, and [turns to Raj] godfather.
- Raj: [touched] Really?
- Howard: Of course.
- Raj: You hear that, Stuart? I’ve got a dog and a godchild, you have nothing!
- Penny: Oh, look at all the babies!
- Sheldon: Some may be successful, some may be homeless. It’s fun to think about.
- Leonard: I wonder which one’s Halley.
- Amy: Kind of hard to see the names.
- Penny: Mm, that one kind of looks like Bernadette.
- Amy: They all look the same to me.
- Raj: Guys, she’s my goddaughter, I think I’ll know when I see her.
- Halley: [cries like Debbie Wolowitz, freaking out the adults]
- Raj: That one.
- Raj: I'm gonna drive like they do in India. [angrily honks horn] GET OUT OF THE WAY, YOU SYPHILITIC DOGS!
- Amy: Well, that was quite a day.
- Sheldon: It was. Bernadette had her baby, I made it to Wizarding World, and now it is time to complete your birthday celebration. Hankius Pankius.
- Amy: I was afraid you’d be too tired.
- Sheldon: Amy, I just saw a magic train and reported somebody for cutting in line. If that’s not foreplay, I don’t know what is. [chases Amy into the apartment]