There are some pretty big differences between The Big Bang Theory and its prequel spin-off series, Young Sheldon. For one thing, "Young Sheldon" is a single-camera series, while "Big Bang" was multi-camera to allow for a studio audience, which was quite a change for the creators of the series. Not only that, but Young Sheldon is completely different tonally, starting out as a fairly standard family comedy before becoming more of a dramedy, giving The Big Bang Theory a whole new context. Instead of just making jokes or referencing later events in Sheldon's life, the show actually expanded on some of the ideas from The Big Bang Theory and made Sheldon Cooper a richer, more complex character. And since The Big Bang Theory was written without any plans to do a prequel series, sometimes that meant they had to retool a few things to make it all make a little more sense.

One of the biggest changes was in the character of George Cooper, Sr., Sheldon's father, played by Lance Barber in Young Sheldon. George Sr. died before the events of The Big Bang Theory, and Sheldon (Jim Parsons) always spoke negatively of him, saying he was an abusive alcoholic and adulterer. In Young Sheldon, George Sr. doesn't always understand his youngest son Sheldon (Iain Armitage), but he does his best to be a good husband and father. In fact, in the seventh season of the prequel series, we find out that George Sr. never cheated on his wife and it was all just one big misunderstanding.

In a season 10 episode of The Big Bang Theory called "The Hot Tub Contamination," an adult Sheldon reveals that the reason he always knocks three times instead of just once is because he saw his father having sex with another woman when he was young and it traumatized him. The first knock is common, but the two extra knocks give someone a chance to compose themselves and put their pants on. Sheldon's three knocks are used to indicate some important points in the show, such as when he deliberately knocks on Amy's door only once so she wouldn't suspect it was him, and shows how much the incident has affected him.

In the Young Sheldon episode "The Ants on the Log and the Cheating Winker", we learn that Sheldon didn't actually see his father with another woman, but that George Sr. and his wife Mary (Zoe Perry) were dating. at a grown-up party with some role-playing, and Mary was dressed as a German barmaid named Helga. George would die of a heart attack within a year of Sheldon's "discovery". and he never confronted his father about it, leading to animosity that would never be resolved. The effects of George's death will weigh heavily on the entire Cooper family, although it is worth noting that Sheldon didn't come home from college for his family's first Thanksgiving after George's death, and the rest of Cooper's crew mourned without him.

The decision to rebuke George Sr.'s infidelity was met with mixed reactions from fans, with some seeing it as a disservice to the Big Bang Theory characterization, while others appreciated it because they loved George Sr. over seven seasons of "Young Sheldon" and didn't want me to suddenly hate him right before his death. Honestly, making George Sr. less of a villain and his relationship with his son more complicated than the grown-up Sheldon he portrayed on The Big Bang Theory was the right move because it not only worked better for the spin-off, but also made an interesting point about the nature of the memory. We are all unreliable tellers of our own stories because we rarely have all the information, and Sheldon spent decades of his life hating his father for something that never happened.

There was love between Sheldon and his father, even if it was hard for both of them to show it. While The Big Bang Theory was more interested in Bazingas and really low-key Star Trek jokes, "Young Sheldon" took an in-depth look at how Sheldon Cooper came to beand in the people who shaped it.