In 2005, the National Academies released the report Guidelines for Human Embryonic Stem Cell Research, which offered a common set of ethical standards for a field that, due to the absence of comprehensive federal funding, was lacking national standards for research. In order to keep the Guidelines up to date, given the rapid pace of scientific developments in the field of stem cell research, the Human Embryonic Stem Cell Research Advisory Committee was established in 2006 with support from The Ellison Medical Foundation, The Greenwall Foundation, and the Howard Hughes Medical Institute. As it did in 2007, the Committee identified issues that warranted revision, and this book addresses those issues in a second set of amendments. Most importantly, this book addresses new scientific developments in reprogramming of somatic cells to pluripotency by adding a new section and revising other relevant sections of the Guidelines.