Aaaaaactually... Gymboree just came out with a 9-12 in their newborn collection. They still have the 6-12 but added the 9-12 and then it jumps to 12-18.
DS is busting out of the 6-12 (tops especially) but the 12-18 are too big for him. I hate that inbetweenness look.
Oh, and he's only 9 months. He's Mr. Torso Man.