Quote from Chandler in The One with Rachel's Sister
Chandler: Come on. Don't take this personally. I just can't have sex with a sick person. Monica: I'm with you, Chandler. I mean, I can't have sex with a sick person either. It's disgusting. But I'm not sick. Let me prove it to you. We are two healthy people in the prime of life. Chandler: See, that's the thing, I would like to stay in the [in congested voice] "prime of life."