This is nuts! They look to be very similar in size and proportion to me. I guess Robyn is quite a bit taller, so her measurements are probably bigger, but still.
As for Jessica Simpson, congratulations to her and her husband (or is it fiancÚ?). My older son was 9 months old when I got pregnant with my younger son. Having them spaced that close together is difficult but rewarding. I hate to see Jessica's weight scrutinized so closely--it's none of people's business. But that just goes along with being in the public eye.