Quote from Barney in Doppelgangers
Marshall: I can't believe this. Now I gotta tell Lily the fifth doppelganger is a fake. Barney: So, what does she care? Marshall: Lily decided that once we spotted your doppelganger, we'd start trying to have kids. Barney: Kids! No! Uh-uh! The rule is, no kids until you're at least 45. Do you ever read my blog? It's gotten a lot better. Marshall: I'm ready to be a dad, you know? But Lily needs some sign from the universe. And now it could be years. Barney: I'm sorry, buddy. That'll be 37.50.