What are stem cells and why are they so powerful?

The answer

Stem cells are undifferentiated cells with the remarkable ability to develop into many different cell types. Embryonic stem cells are 'pluripotent,' meaning they can become any of the body's 200+ cell types. Adult stem cells, found in bone marrow and other tissues, are more limited but still repair and replace damaged cells throughout your life. The discovery that ordinary cells can be reprogrammed back into stem cells (induced pluripotent stem cells) by Shinya Yamanaka in 2006 won the Nobel Prize and opened the door to personalized regenerative medicine.