Paths to a Person

摘要

What stem cell researchers are really studying is how your body was made and how to do it all over again. Embryonic stem cells (or the newer induced-without-embryos variety) can travel down any of the paths below to become skin, heart, brain and other body parts. So-called adult stem cells are stuck in the middle, able to become certain types of cells but not others. In nature, cells don't travel backward on these developmental paths; stem cell researchers hope to treat disease by getting them to do just that.