Congratulations!!!!! Get your doctors opinion, but if he says that he's eating to much and will be fat, please get a second opinion elsewhere. I have two boys, 3 yrs old and 5 months old. My husband also has a 15 year old from a previous marriage. All of them where fat as babies. My step son won a champion chubby contest! He is sclupted and very healthy.
My first son was born at 7lbs 6oz. I'm looking at his weight recording now and it says, 11.12lbs at 34 days, 16.8lbs at 19wks...He got so fat and adorable! He breastfed and almost never ate solids. He started to really eat when he turned 2 years old. Now he's thin, strong and active.
My 5 month old was born at 7lbs 2oz. He's was 18lbs 4oz at 21 weeks! I think he chubbier than my first.
My best friend has had super chubby babies too. My husband was tubby as a child and so was my brother....Don't worry. I don't know if it's the norm, but it is common. And very cute! He'll loose it when he starts walking.