Harvesting ESC without destroying embryos

Scientists testify to the US President's Council on Bioethics that there are two ways to harvest embryonic stem cells without destroying viable human embryos. One method is to use embryos which have spontaneously stopped dividing. (Reference: DW Landry and HA Zucker J Clin Invest. 2004 Nov;114(9):1184-6.) Another concept is to alter genes prior to cloning so that normal development is not possible, harvest cells, and turn the genes back on. (Reference: WB Hurlbut)