The word cloning is used by scientists to describe many different processes that involve making duplicates of biological material. In most cases, isolated genes or cells are duplicated for scientific study, and no new animal results. Stem cells are unique and essential cells found in animals that are capable of continually reproducing themselves and renewing tissue throughout an individual organism's life. Stem cells can be obtained from human embryos. Both cloning and embryonic stem cell research has focused public attention on the meaning and status of human embryos in contexts essentially unrelated to abortion. As a result, society and the law have begun to construct new understandings of the term embryo. Those understandings merge with and reshape old understandings. Thus, the politics of abortion are being transformed as society responds to developments in molecular biology, especially the advent of mammalian cloning in 1997 and the isolation of human embryonic stem ce...