How do we know this? Because the librarian’s religion became a minor plot point in a first-season episode.
Sheldon Cooper (Iain Armitage) — a boy genius lacking in social skills — does not believe in God. That’s true of the adult version of the character viewers have seen since 2007 in "The Big Bang Theory”; it’s also true of the 10-year-old version who’s at the center of the hit spinoff, which debuted a year ago.
Sheldon’s mother, Mary (Zoe Perry), on the other hand, is a true Bible-thumping believer — a regular churchgoer who drags her family along with her.