An MIT researcher has discovered how to temporarily make adult stem cells multiply like embryonic stem cells. This will be very useful when building stem cell lines for research, and gives further insight into the way in which such cells work. A quote: "If we want to do cell replacement therapy with stem cells, we have to be able to monitor them and avoid mutations that cause tumors in people." This research is a great step forward in that direction. You can learn more about stem cells at InfoAging.org.