Desc: Stem Cell Universe with Stephen Hawking: Directed by Geoffrey Sharp. With Stephen Hawking, Michael C. Hall, Krstin Baldwin, Vincent Giampapa. Led by a pioneer in the science world, Stephen Hawking, this special takes us on a journey which delves into the subjects of stem cells both embryonic and adult to explore what these wondrous and baffling mechanisms are capable of, what exactly stem cells are and if they are the key to our future or a ticking time bomb waiting to detonate?