David Letterman and longtime girlfriend Regina Lasko celebrated the birth of their first child, son Harry, just before midnight on Monday. Letterman broke the news on Tuesday's Late Show. "First thing I took him home and dangled him over the balcony," joked the 57-year-old funnyman, who named his first-born after his late father. Naturally, Letterman used the birth as fodder for his top 10 list. Among the reasons the late-night vet was excited to be a dad: "There is now tangible evidence I have sex." Eh, I'm still not convinced.