While the field of human embryonic stem cell research receives a tremendous amount of public attention, many scientists are also exploring the potential of adult stem cells for possible therapies. But this field raises other difficulties. Although adult stem cell research isn’t fraught with the controversies that surround embryonic stem cells, adult stem cells are extremely difficult to isolate and then to multiply in a lab dish. Now, as reported in the May 6 issue of the journal Cell, researchers in the lab of Whitehead Institute Member Rudolf Jaenisch have discovered a mechanism that might enable scientists to multiply adult stem cells quickly and efficiently.