Studies in mice show that genetically matched embryonic stem cells can be generated from unfertilized eggs and used for transplantation, report scientists at Children's Hospital Boston and Harvard Medical School, in Boston, and the Harvard Stem Cell Institute, in Cambridge, Mass (Kim K et al. Science. doi:10.1126/science.1133542 [published online December 14, 2006]).
By activating mouse eggs through chemical treatment, scientists produced stem cells that could be transplanted into mice matched for the major histocompatibility complex antigens of the egg donor. These cells (which were halted during meiosis and have 46 chromosomes) differentiated into various tissues types without the need to suppress the recipient's immune system.
Hampton T. Embryonic Stem Cells. JAMA. 2007;297(5):459. doi:10.1001/jama.297.5.459-a