How to Build a Beating Heart

Science may be on the verge of producing a limitless supply of replacement parts by regenerating damaged or aging body parts grown from our own cells. Imagine the implications if we could custom make body parts genetically indistinguishable from our own. Could it eliminate the death sentence for profound birth defects, the need for prosthetics and any shortage of transplant organs? National Geographic delves into the science of tissue engineering and tracks how scientists are beginning to harness the body's natural powers to grow skin, muscle, body parts and vital organs, even hearts.