Intro: Organ transplantation has come a long way in recent years. For example, kidney transplants are very successful operations. But unless a patient gets an organ from an identical twin, he's stuck taking medication to suppress his immune system so the body doesn't reject it. Doctors at Mayo Clinic want to change that. They're researching ways to grow organs from a patient's own stem cells. It's called regenerative medicine, and it offers hope for a solution to organ rejection.