It’s the Sheldon Cooper origin story we didn’t know we needed — and one we certainly never expected to receive.
During Young Sheldon Season 5, Episode 6, “Money Laundering and a Cascade of Hormones,” Adult Sheldon (voiced by Jim Parsons) revealed why he’s always referred to sex as “coitus” on The Big Bang Theory. It all started when twin sister Missy began asking some “uncomfortable questions” at church, which prompted youth pastor Rob (played by recurring guest star Dan Byrd) to suggest to Mary and Pastor Jeff that they talk to the Sunday School kids about the birds and the bees. The discussion was ultimately called off, but the commotion it caused taught Sheldon that the very mention of “S-E-X” can wreak havoc on society.
“Every culture has their taboos,” Adult Sheldon explained. “In the Ukraine, it’s rude to whistle in doors — and they’re correct. Not a fan,” he pointed out, reinforcing his no-whistling policy first cited in Big Bang Season 2.
“In our society, any discussion of human reproduction seems to be so upsetting that it causes chaos,” he continued. “Even the word ‘sex’ provokes an uncomfortable reaction. I thought ‘fornicate’ might work, but that seemed too judgy.”
It’s at that point that 11-year-old Sheldon reached for his thesaurus to find an alternative, and that’s when he landed on the perfect word — “a word so bland and clinical that it would be impossible to take offense to it.”
Though never a catchphrase per se, Dr. Cooper employed the word “coitus” throughout all 12 seasons of The Big Bang Theory. (The origin story behind his actual catchphrase, “Bazinga,” was revealed midway through Young Sheldon Season 2.)
Another Young Sheldon origin story is already confirmed for the Nov. 18 episode, which will examine the boy genius’ complicated relationship with engineering — with a little help from fellow Big Bang Theory alum Simon Helberg, who will reprise his role as CalTech engineer Howard Wolowitz in a voiceover capacity (watch sneak peek).