Embryonic stem cells: Looking up
FOURTEEN years ago James Thomson of the University of Wisconsin isolated stem cells from human embryos. It was an exciting moment. The ability of such cells to morph into any other sort of cell suggested that worn-out or damaged tissues might be repaired, and diseases thus treated—a technique that has come to be known as regenerative medicine. Since then progress has been erratic and (because of the cells’ origins) controversial. But, as two new papers prove, progress there has indeed been. (...)
