Stem cell research raises important bioethical issues. Stem cells have the potential to develop into all body tissues, and they may be able to replace diseased or defective human tissue. The best source for these cell clusters is human embryos, which are destroyed when the stem cells are extracted. Opponents to the research, including any on the religious right who also oppose abortion, argue that the embryo is a potential human life and therefore should not be destroyed for the sake of science. But proponents of the controversial research say that a variety of treatments and cures for diseases could be gained through scientific advancements made because of stem cell research. Supporters add that the embryos cannot develop on their own, and therefore should be put to use for the sake of better medicine—which could help people who suffer from many different diseases, including diabetes, Alzheimer’s, and Parkinson’s, thus improving and extending human life. (It is important to note that the embryos exist in laboratories because of advances previously made in reproductive science.)

In August 2001 the George W. Bush administration moved cautiously forward on the issue by allowing stem cell research as long as it is limited to existing cells, the embryos having already been destroyed. In other words, new stem cells cannot be created strictly for the purpose of laboratory work. Bush said he concluded that federal funding should be used to support research on 60 existing genetically diverse stem cell lines, which have the ability to regenerate themselves indefinitely. The president acknowledged the complexity of the issue, saying in a radio address, “At its core, this issue forces us to confront fundamental questions about the beginnings of life and the ends of science. It lies at a difficult moral intersection, juxtaposing the need to protect life in all its phases with the prospect of saving and improving life in all its stages.”But, he added, for the existing stem cell lines, “the life and death decision has already been made.” Over the next few years, state legislatures took up the issue, creating a patchwork of policies across the nation by 2005.