In the Washington Post, writes: Late last year, separate teams of Japanese and American researchers announced that they had produced pluripotent stem cells, or cells that retain the ability to become any body cell, by using gene insertion technology that causes body cells to revert to embryonic status. This technology has been applauded by many, including religious conservatives, because it appears to obviate the need to destroy human embryos. Yet obstacles to effective research, and to potential cures, remain. The pluripotent stem cells created through this technology have, for example, a tendency to become cancer cells. This renders them too dangerous for transplant purposes. Most researchers agree that we have to keep open multiple pathways, not least of all the proven method of producing stem cell lines from human embryos.