Lily: Okay, now you're being ridiculous. An hour ago, you didn't even think there was a problem.
Marshall: Well, I was just putting on a brave face. Okay, think about it. We've had unprotected sex 203 times in the past four months. [Marshall and Lily high five] Obviously I'm the problem.
Barney: Problem?! You can't get a girl pregnant. That's the dream. I'd give my firstborn to not be able to have children.