Martin: Can you imagine? Lilith's and my kid would be brother to you and Niles and Freddie.
Frasier: What are you talking about?
Martin: And if you and Lilith got back together, you'd be his step-father and his brother and Niles would be your son and his own uncle. It's almost worth doing just so that I can tell the story.

Lilith: Frasier, don't misunderstand, I'm not proposing any change in our relationship.
Frasier: Would we... sleep together?
Lilith: I thought we'd freeze your sperm.
Frasier: Is that a "yes" or a "no"?

Lilith: I want to have another baby.
Frasier: Well, you certainly don't need me for that. Surely... someone in Boston must have sperm.
Lilith: I came to you first so that Frederick could have a full sibling.
Frasier: So, just like that we're going to have another baby together.
Lilith: No, no, no. Not just like that. I mapped out our dominant and recessive traits on a genome square, applied Mendel's laws, allowed for anomalies and concluded that you are the best biological choice.
Frasier: I see. Well, as enticed as I am by your honeyed words, I'm gonna need some kissin'.