If Not Now - S12-E11
Factual error: The male patient tells ER doc that "Six years ago, l find out l inherited the Philadelphia chromosome. Ran on my mother's side of the family. L never knew. Screwed by genetics." The Philadelphia Chromosome, the cause of CML Leukemia, is not inherited. It occurs spontaneously in an individual, usually due to chromosome damage caused by radiation, and cannot be passed on to a person's children.
Answer: It was in "Chaos Theory", the first episode of season 9 (time code 00:13:55).
Super Grover ★