Human embryonic stem cells are often described as "master cells," able to develop into any other type of cell in the human body. Research on embryonic stem cells has given rise to ethical debates, as the removal of an embryonic stem cell from an embryo typically involves the destruction of that embryo. In 2007, researchers in Japan and the United States published reports that they had successfully induced adult human somatic cells to exhibit characteristics similar to embryonic stem cells. Some have argued that these new induced pluripotent stem cells render embryonic stem cell research unnecessary, while others contend that continued embryonic stem cell research is still important. This book consists of public domain documents which have been located, gathered, combined, reformatted, and enhanced with a subject index, selectively edited and bound to provide easy access.