Science Questions explores stem cell therapy and its potential to transform the treatment of human disease. Adult stem cells have been used to treat leukemia since the late 1950s. Among early attempts to do this were several bone marrow transplants conducted in France following a radiation accident. Since physicians could not isolate stem cells at that time, they transfused bone marrow with stem cells in it. The research has come a long way and now researchers at the University of Utah are among the first in the nation to lead clinical trials on the injection of stem cells into human hearts.