On this week’s The Big Bang Theory, Bernadette tells Howard that she is pregnant through Post-It notes she places around the kitchen. At first he is excited, but that quickly turns to panic when he starts getting anxiety about being a good parent.

Howard tells the guys that Bernadette is expecting. Leonard and Raj are excited, but Sheldon is disappointed because he thinks that having a baby in the mix will ruin everything. That is when Leonard points out that it will be the second baby in the group, referring to Sheldon as the first.

Howard’s freaking out continues, as he tells the guys that he isn’t fit to be a father and that it will be really expensive. They try to calm him down and assure him that it is a good thing. Well, except for Sheldon. Howard agrees with them, but says he feels overwhelmed. That is when they decide that they should go out and celebrate. They find themselves at a bar where they get drinks with little umbrellas. Sheldon gets drunk, while Howard tries to come up with an invention so he can help support his kid.

Meanwhile, Bernadette tries to tell the girls, but her announcement gets spoiled when Penny receives a text from Leonard with the news. When they notice that Bernadette doesn’t seem too excited, she confesses that Howard didn’t react the way she expected he would.

Bernadette then reveals to the girls that her pregnancy wasn’t planned. She says one night, she and Howard got a little spontaneous and reckless. She then drops the bomb that it happened on Sheldon’s bed. One night when they were at the apartment, they got bored by Sheldon talking about time zones and railroad schedules. Bernadette got up to go to the bathroom, while Howard was just leaving the bathroom. That is when Howard led her to Sheldon’s room. After being shocked by the news, Penny gets a text from Leonard asking if they would like to join them at the bar to do karaoke. Sheldon also texts Amy inviting her. She can tell that he is drunk because he uses a period instead of a question mark.

The girls walk in and find that Raj is already on the stage singing. Howard pulls Bernadette aside and apologizes to her for the way he reacted. She tells him that it’s okay to be nervous. They both agree that they are really excited.

After talking things out with Howard, Bernadette sits on the stage as Penny and Amy sing Justin Bieber’s song “Baby” to her. Leonard and Raj follow it up with Salt-N-Pepa’s “Push It.” Sheldon then goes in a different direction, singing “My Country Tis of Thee.” Howard then takes the stage and attempts to sing Paul Anka’s “She’s Having My Baby.” He doesn’t get too far into the song before Sheldon interrupts him, having found out that they had coitus in his bed.

At the end of the episode, Leonard and Penny discuss how they want to be parents one day. Sheldon chimes in from the couch, asking them to keep it down. His face is covered in magic marker and he is wearing lipstick. Penny decides that maybe they might lack maturity as she holds up the marker.