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Big Bang Theory Mystery Solved: Young Sheldon Reveals Why Sheldon Doesn't Say 'Sex'

Ian Armitage on Young Sheldon
(Image credit: CBS)

Over The Big Bang Theory’s 12-season run, Sheldon Cooper’s quirks and eccentricities were fodder for his cohorts as well as the show’s fans. Amid all of these traits, there were a few oddities that stuck out. One was Sheldon's use of the word “coitus," which he would use whenever sexual relations or related subjects were brought up. For some, hearing the term may have been a bit weird in the beginning but, eventually, it became just another signature Cooper-ism. Interestingly enough, the show never revealed why that Cooper's term of choice. Now, years after Big Bang's end, its spinoff, Young Sheldon, has finally provided the answer.

The reveal ultimately arrived during the sixth episode of Season 5 --  “Money Laundering and a Cascade of Hormones.” The origin of “coitus” was sparked when Sheldon Cooper’s twin sister, Missy, began asking questions about sex, according to TVLine. After a huge commotion broke out regarding a possible Sunday school sex talk, Cooper became aware of the sensitivity surrounding the subject. On the show, adult Sheldon (still voiced by Big Bang Theory alum Jim Parsons) said about the community discourse over “sex”:

Every culture has their taboos… In our society, any discussion of human reproduction seems to be so upsetting that it causes chaos. Even the word ‘sex’ provokes an uncomfortable reaction. I thought ‘fornicate’ might work, but that seemed too judgy.

Of course, in true Sheldon Cooper fashion, the young man took to the thesaurus and came across the clinical term. According to the older version of Cooper, he found the term “coitus’ to be “so bland and clinical” that others would never “take offense to it.” Ultimately, he was right about the clinical term being inoffensive and not causing any kind of uproar. Though with this in mind, it's ironic that in reality, the character's use of the word sparked a lot of discussion among viewers.

Though he would use the phrase from time to time, the usually A-type and neurotic character initially wasn't to keen on participating in the actual act himself. He originally viewed “coitus” as simply a transactional release between two people. But as the character evolved over the years, sexual intercourse became a bi-annual event for him and his girlfriend, Amy Farrah Fowler. And ultimately, the act became more regular after the couple was married. All in all, this makes for a very interesting through line for both shows.

It's fun whenever the prequel series offers Big Bang Theory fans the chance to see how Sheldon Cooper became the quirky and beloved scientist fans watched for over a decade. With Young Sheldon airing its fifth season, viewers will continue to learn more about him and they can do so by tuning in to CBS on Thursdays at 8 p.m. ET. And you can also stream the show and its predecessor on HBO Max.

Adreon Patterson

A boy from Greenwood, South Carolina. CinemaBlend Contributor. An animation enthusiast (anime, US and international films, television). Freelance writer, designer and artist. Lover of music (US and international).