You guys need to read the question. Do you become an ob/gyn by taking an internal medicine residency? No! As far as the real answer goes: Everything to do with internal medicine has little surgery connected to it. Cardiology has cardiothoracic surgeons and gastro has colorectal surgeons, etc. The fields and knowledge required is too vast and a waste of time to do both. If you are just naturally rich and just want to have fun do a 5 year residency in cardio and another 5 in gen. surgery!