Quote from Marshall in Mystery Vs. History
Barney: You guys are idiots! Future Ted: Okay, not completely dead. Barney: You are seriously telling me you don't want to open that envelope and find out if you're having a boy or a girl? Lily: Nope. Dr. Sonya only gave us this in case we wanted to know. Marshall: But we don't. Lilypad and I are just gonna wait till that baby pops out and enjoy the big surprise.