In "The Big Bang Theory" Season 10 episode "The Hot Tub Contamination," Sheldon confides in Penny about catching his father cheating when he was 13. This was a significant moment for their friendship and showed how much Sheldon trusted her. However, the revelation is cheapened in "Young Sheldon" when it is revealed that Sheldon's twin sister Missy has known about their father's cheating tendencies for a long time.

Missy gets to confront their father about secretly meeting another woman, which could potentially lead to the breakdown of their parents' marriage. The sensitivity of the matter makes it tricky for "Young Sheldon" to tackle, but the show may have to incorporate it to stay true to established canon.