of High-Purity Definitive Endoderm from Human Parthenogenetic Stem Cells using an in vitro Analog of the Primitive Streak," by Nikolay Turovets et al., in Cell Transplantation, Vol. 20, No. 6; June 2011 U.S. stem cell scientists breathed a sigh of relief this July when a federal judge upheld the Obama administration’s expansion of stem cell research. He ruled that work on existing embryonic ste...