What are stem cells? – Craig A. Kohn View full lesson: http://ed.ted.com/lessons/what-are-stem-cells-craig-a-kohn Is personalized medicine for individual bodies in our future? Possibly -- with the use of stem cells, undifferentiated cells with the power to become any tissue in our bodies. Craig A. Kohn describes the role of these incredible, transforming cells and how scientists are harnessing their medical potential. Lesson by Craig A. Kohn, animation by Qa'ed Mai.