San Francisco— When researchers first demonstrated in 2007 that human skin cells could be reprogrammed to behave like stem cells that can fully differentiate into other cells, scientists and politicians alike rejoiced. All the potential of embryonic stem cells might be harnessed with the new techniques—without the political and moral controversy associated with destroying a fertilized egg.
Although Kato called human reproductive cloning directly from pis cell lines “very hypothetical,” he pointed out progress for that possibility when he noted that three teams had produced mouse clones from iPS cells. Less expensive and more efficient than the process that produced Dolly the sheep, the iPS approach also would skirt the language of many current prohibitions against human reproductive cloning. Some bioethicists have called for a new international ban that would clearly prohibit the implantation of a human clone in part because of the tantalizing research uses for nascent embryos.