The Big Bang Theory's Sheldon Cooper Has A Character Detail That Makes No Sense

"The Big Bang Theory" intentionally avoids addressing some of Sheldon Cooper's (Jim Parson) conditions. Certain things are implied, of course, and viewers don't need exposition to figure it out. However, the series also definitively makes it clear that he's a hypochondriac and germaphobe who is supposed to have asthma. That said, his asthma might just be a product of his health-related anxieties (or poor writing), as the proof says otherwise.

In season 3's "The Fuzzy Boots Corollary," Leonard (Johnny Galecki) considers getting a cat to distract him from Penny (Kaley Cuoco) dating some hot guy. Sheldon objects to the idea, though, as he's allergic to felines. However, Leonard assures him that the one he wants is a hypoallergenic calico that was developed by a geneticist in San Diego, so Sheldon needn't worry about sneezing.

Ultimately, Leonard decides not to get the cat after Penny agrees to grab dinner with him. While the date (if you can even call it that) doesn't go according to plan, he makes peace with the fact that she isn't interested in him at this point in time. As such, he doesn't get a cat, and we don't find out if the feline would have triggered Sheldon's asthma — though another episode proves that Sheldon's allergy claims might have been overblown.

"The Big Bang Theory" is full of plot holes, but Sheldon Cooper's cat allergy is one of the most glaring ones from the show's 12-season run. The aforementioned episode led us to believe that he couldn't be around felines, but season 4's "The Zazzy Substitution" proves otherwise. In this one, he adopts several cats after Amy Farrah Fowler (Mayim Bialik) dumps him, and not once does he show signs of asthma.

For the sake of giving the show's creators the benefit of the doubt, though, we can also argue that Sheldon was exaggerating when he said he had asthma. His hypochondriac nature means that he always assumes the worst when it comes to his health, so maybe he thought he was allergic to cats, only to realize that he wasn't when he adopted some to cope with heartache.

Mind you, "The Big Bang Theory" made other significant changes to Sheldon as the series progressed, so having him overcome an aversion to cats — and realize that they don't make him sick — isn't beyond the realm of possibility. At the same time, the show's history of plot and character inconsistencies suggests that the creators might have retconned this storyline, so we will never know for sure.

You can catch up with Sheldon (and his cats) by streaming "The Big Bang Theory" on HBO Max.