Stem cells are cells that can change into other types of cells. Embryonic stem cells are able to transform into a wide variety of types of cells, while adult stem cells can become a limited number of types of stem cells. Possible conditions that might benefit from stem cells are diabetes, heart disease, cancer, spinal cord injury, genetic diseases, and more. Testing is still required to deteremine if stem cell treatment would be safe and effective in each of these cases. Follow the links below to find WebMD's comprehensive coverage about how stem cells work, stem cell research, controversy about using embryonic stem cells, and much more.