Leonard: Just tell me the truth, Mother. Was my whole childhood just one big experiment?
Beverly Hofstadter: Of course not, dear. It was thousands of small experiments.
Leonard: So that's all I was to you, a-a test subject?
Beverly Hofstadter: No, you were my baby and I found you fascinating.
Beverly Hofstadter: Yes, watching you develop, tracking your progress. I know I'm not the warmest of parents, but it was time we spent together, and, honestly, those are some of my fondest memories.
Leonard: When did you stop?
Beverly Hofstadter: Oh, I can't tell you. The experiment isn't over.