Stem cell therapy is the replacement of diseased, dysfunctional or injured cells with either adult or embryonic stem cells. It's somewhat similar to the organ transplant process but uses cells instead of organs. Stem cell therapy is sometimes called regenerative medicine. Researchers grow stem cells in the lab. These stem cells are manipulated to make them specialize into specific types of cells, such as heart muscle cells, blood cells or nerve cells. This manipulation may involve changing the material in which the stem cells are grown or even injecting genes into the cells. The specialized cells are then implanted into a person. If the person has heart disease, the cells would be injected into the heart muscle. The normally functioning implanted heart cells, in theory, could replace the defective heart cells. Yes, stem cell transplants, also known as bone marrow transplants have proved highly successful in treating a number of cancerous diseases such as leukemia and aplastic anemia.