The Big Bang Theory Season 12 Episode 12

The Big Bang Theory Season 12 Episode 12

Penny’s ex-boyfriend, Zack, 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.

Episode Title: The Propagation Proposition

Air Date: 2019-01-10

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