In episode " The Conference Valuation " (S12E17), the story splits between a high-stakes pharmaceutical convention in San Diego and a chaotic "science day" back in Pasadena. The Pharmaceutical Convention
Danny offers Penny a job, leading her to realize she doesn't always feel appreciated by Bernadette.
Leonard realizes his mother, Beverly, performed similar experiments on him throughout his childhood. When he calls her to complain, she reveals that the "experiment" on him never actually ended. [S12E17] The Conference Valuation
Sheldon and Amy use the children to test cognitive and motor skills, much to Howard's amusement and Leonard's distress.
Bernadette eventually fights to keep her, and Penny declines the rival offer, though Bernadette secretly keeps a napkin with Danny's high-salary offer hidden from Penny. The "Guinea Pig" Day In episode " The Conference Valuation " (S12E17),
Penny and Bernadette travel to San Diego to promote a new drug. Penny, thriving in her role as a sales lead, catches the attention of Danny, a representative from a rival company that Bernadette despises.
It is revealed that Amy intentionally brought the book to spark Sheldon's interest in having their own children—a plan that seemingly works as Sheldon begins discussing the logistics of having triplets or quintuplets. When he calls her to complain, she reveals
Back at home, Howard is left alone with the kids and invites the guys over for company. The day takes a turn when Sheldon finds a book on developmental experiments for children.