The Big Bang Theory started off quietly in Canada, but managed to garner major success in later seasons. The Big Bang Theory is telecast throughout Canada via the CTV Television Network in simultaneous substitution with cross-border CBS affiliates. Now immensely popular in Canada, The Big Bang Theory is also rerun daily on the Canadian cable channel The Comedy Network.

Two months after the events of "The Change Constant", Sheldon and Leonard repair Sheldon's DNA molecule model as everyone prepares to fly to Sweden for the Nobel Prize award ceremony. Howard and Bernadette nervously leave their kids for the first time with Stuart and Denise, while Raj leaves his dog with Bert. Penny has become pregnant, though she and Leonard are keeping it a secret. On the flight, Raj thinks he spots Sarah Michelle Gellar. Penny's frequent bathroom trips make Sheldon fear she is sick. Leonard reveals the pregnancy to Sheldon, but instead of being excited for Penny, Sheldon is only selfishly relieved that he will not get sick and he exposes the pregnancy, offending Leonard. At the hotel, a series of minor incidents with their kids make Howard and Bernadette want to go home. Much to their dismay, Sheldon is still insensitive. Amy furiously tells Sheldon he broke their friends' hearts and they only tolerate him because he does not intentionally do so, which she also sometimes does. Everyone decides to stay for the ceremony and Raj brings Gellar. After they are awarded their medals, Amy encourages girls to pursue science while Sheldon thanks his family and then individually acknowledges each of his friends and Amy as his other family who always support him. The episode closes with the gang eating in Apartment 4A (an allusion to the final scene in the opening credits) as an acoustic version of the theme song's chorus plays.
Howard dresses as Sheldon for Halloween at work, hurting Sheldon's feelings. When Howard does not apologize, Amy and Sheldon dress as Bernadette and Howard at Penny and Leonard's party, angering Bernadette. Sheldon and Bernadette later bond over their painful childhood memories. Leonard is upset that Penny does not seem to remember that their first kiss was on Halloween. Penny later admits she does remember, but does not like to think of their first kiss as an unromantic drunken hookup. She likes to imagine their first kiss was one they shared on Leonard's birthday, which pleases him.

In the show, the song "Soft Kitty" was described by Sheldon as a song sung by his mother when he was ill. Its repeated use in the series popularized the song.[83] A scene depicting the origin of the song in Sheldon's childhood is depicted in an episode of Young Sheldon, which aired on February 1, 2018. It shows Sheldon's mother Mary singing the song to her son, who is suffering with the flu.[84]
Professor Proton, Sheldon's favorite childhood show, is being rebooted. After unsuccessfully auditioning for the part, he goes to Wil Wheaton for acting tips for his second audition. However, Sheldon is later dismayed when Wil is offered the role instead. Talking it over with Arthur in his dreams, he is still upset to see his idol replaced and considers Wil an enemy again. Meanwhile, Howard gets a vasectomy while Bernadette is on bed rest. Penny offers to take care of Halley for them, but they insult her by expecting her to be irresponsible. Halley ends up saying her first word by calling Penny "Mama."
When Leonard receives a braggy Christmas letter from his brother, he feels bad about how little he and Penny have achieved in the past year. Leonard wonders if he and Penny should be thinking about the next step after two years of marriage, like buying a house or having a baby. Penny tells him she wants to do all those things someday, but she has a bunch of stuff she would like to do first.
Kunal Nayyar has the flick Think Like a Dog in post-production and the upcoming Trolls World Tour in pre-production. Nayyar provides the voice of Guy Diamond in the movie series. Aside from that, however, the former Raj Koothrappali is looking forward to some much needed family time. "I'm going to go to India, spend more time with my parents," he told Parade in late April. "I left my country when I was 18, so it's important for me to go home and spend time with mom and dad, so that's the main focus right now.

After the birth of Michael, Howard and Bernadette are unsure who should stay home with the kids. Howard decides to look after the kids one day to show he has what it takes to care for them. While Bernadette falls back in love with her job on a trip to the office, Howard is quickly tired and realizes he might not have what it takes to be a stay-at-home dad. Howard and Bernadette realize neither them is ready to give up their job.
^ "Editor's Note: With final Monday ratings in, The Big Bang Theory has now reached a new series high in viewers (16.32m) and was the night's top program in adults 18-49 (5.9/15), up a tenth from this morning. -- "Two and a Half Men" Soars to Its Best Adult 18-49 Rating in Three Years". CBS. March 9, 2010. Archived from the original on January 8, 2014. Retrieved January 5, 2013.
×