The Big Bang Theory Fans Can't Get Over The Mistake Involving Sheldon's Asthma And Allergies
"The Big Bang Theory," like many classic sitcoms, is riddled with plot holes. Take, for example, the opening scene of the pilot where Leonard (Johnny Galecki) and Sheldon (Jim Parsons) go to make deposits in a sperm bank for money and Sheldon says "Leonard, I don't think I can do this" to which Leonard replies "What, are you kidding? You're a semi-pro." This scene implied that Sheldon has a sex drive, something contradicted by later episodes. This might be a hold over from the original unaired pilot, in which Sheldon is seen to be more sexual and have more of a romantic history with women.
In the episode "The Maternal Capacitance," Penny mentions that her father's name is Bob, but in later episodes her father's name was changed to Wyatt (Keith Carradine). Having a spin-off prequel has created even more inconsistencies, such as when Lance Barber played Leonard's former bully Jimmy Speckerman in "The Speckerman Recurrence" but then took up the role of Sheldon's father in "Young Sheldon."
Still, there are some plot holes that fans can forgive, and some that they apparently can't. While most fans overlook Lance Barber's multiple appearances, few are able to look past the inconsistencies with Sheldon's allergy to cats, which came up in a Season 1 episode and seemed to disappear by Season 4.
What happened to Sheldon's cat allergies?
In a Reddit thread in the r/bigbangtheory subreddit, fans were asked if they noticed any major plot holes in the series and u/Significant_Curve286 brought up a doozy of a hole. As that user points out, Sheldon tells Leonard in the Season 1 episode "The Fuzzy Boots Corollary" that they can't get a cat for the apartment because he has allergies and asthma, but in the Season 4 episode "The Zazzy Substitution," Sheldon adopts several cats and keeps them in his room following his breakup with Amy. A number of people such as u/Y0ukn0w_wh0, however, pointed out that Sheldon could have easily lied about his allergies to keep Leonard from getting a pet that he didn't want.
There is another possible explanation, however. According to Healthline, it is possible to grow out of an allergy over time, particularly if the allergy first appeared in childhood. Thus, it's possible that Sheldon had an allergy to cats at one point, but gradually grew out of the allergy at some point between Seasons 1 and 4. It wouldn't be the first time that Sheldon proved to be an unreliable source of information about his own life, as he repeatedly talks about his father on "The Big Bang Theory" as an abusive monster, something that all "Young Sheldon" watchers know to be untrue. So it's certainly possible that an explanation could be given to explain away the plot hole surrounding Sheldon's allergies, but without any explanation on the show, the hole continues to frustrate fans.