Episode Titles: Propagation

 You are viewing a list of 1 The Big Bang Theory episode featuring "Propagation" in their title.

  • The Propagation Proposition

    The Propagation Proposition
    Season 12, Episode 12 - Aired January 10, 2019

    Penny's ex-boyfriend, Zack (Brian Thomas Smith), and his wife want a baby, but when Zack is infertile, they ask Leonard for help. Also, Koothrappali attempts to mend things with his ex-fiancée, Anu.