specialized cells is like peeking into the earliest development of the many tissues and organs of the human body. Stem cell research may help clarify the role genes play in human development and how genetic mutations affect normal processes. They can be used to study how infectious agents invade and attack human cells, to investigate the genetic and environmental factors that are involved in cancer and other diseases, and to decipher what happens during aging. Stem cells may also revolutionize traditional chemical medicine. Because embryonic stem cells can continue to divide for long periods of time and produce a variety of cell types, they could provide a valuable source of human cells for testing drugs or measuring the effects of toxins on normal tissues without risking the health of a single human volunteer. In the future, thousands of compounds could be quickly tested on a wide assortment of cell types derived from stem cells, making drug discovery more efficient and cost effective. Using nuclear transfer to produce stem cells could be particularly useful for testing drugs for disorders that are of genetic origin. For example, it is difficult to study the progression of Alzheimer’s and Parkinson’s diseases in the brains of live patients— but by using the cells of an Alzheimer’s patient to create stem cell lines with nuclear transfer, scientists could trace the development of the disease in a culture dish and test drugs that regenerate lost nerve cells with no danger to the patient. Stem cells may also help scientists calculate the effects of toxic substances in drugs, food, and the environment. 18 Courtesy of Dr. Leonard I. Zon. WHY STEM CELL RESEARCH IS BEING PURSUED The Role of Stem Cells in Basic Research Scientists and society as a whole must consider the ethical implications of stem cell research. As discussed throughout this booklet, different ethical issues are raised by the wide range of stem cell research activities. In 2005, the National Academies published guidelines for scientists who do research with human embryonic stem cells to encourage responsible and ethically sensitive conduct in their work. Although the guidelines are not expressly legally binding, many researchers have voluntarily adopted them as a guide to what constitutes appropriate conduct in human embryonic stem cell research. Yet for some people, such guidelines are inadequate because they aim to govern a practice that they see as intrinsically unethical. As the science advances, it is essential that scientists; religious, moral, and political leaders; and society as a whole continue to evaluate and communicate about the ethical implications of stem cell research. Is an Embryo a Person? The controversy over embryonic stem cell research touches on some of the same fundamental questions that society has grappled with in the debates over contraception, abortion, and in vitro fertilization. The questions at the center of the controversy concern the nature of early human life and the legal and moral status of the human embryo. Embryonic stem cell research often involves removing the inner cell mass from “excess” blastocysts that are unneeded by couples who have completed their fertility treatment. This prevents those blastocysts from continuing to develop. Although such blastocysts would likely be discarded (and thus destroyed) by the clinics in any case, some believe that this does not make it morally acceptable 19 ETHICS, MORAL VALUES, AND U.S. LAW The National Academies published the Guidelines for Human Embryonic Stem Cell Research in 2005. Here, members of the committee present at a report briefing. to use them for research or therapeutic purposes. They believe that the life of a human being begins at the moment of conception and that society undermines a commitment to human equality and to the protection of vulnerable individuals if blastocysts are used for such purposes. Some cultures and religious traditions oppose the use of human life as a means to some other end, no matter how noble that end might be. Other traditions support embryonic stem cell research because they believe that the embryo gains the moral status of a human being only after a few weeks or months of development. Many traditions emphasize obligations to heal the sick and ease suffering—goals for which embryonic stem cell research holds great potential—and favor embryonic stem cell research for this reason. Several religious groups are currently involved in internal discussions about the status of the human embryo and have not yet established official opinions on the matter. Public opinion polls suggest that the majority of both religious and non-religious 20 ETHICS, MORAL VALUES, AND U.S. LAW The National Academies’ Guidelines for Human Embryonic Stem Cell Research In order to provide all scientists—those working in universities and private companies and with both public and private funding—with a common set of scientific and ethical guidelines, the National Academies published the Guidelines for Human Embryonic Stem Cell Research in 2005. The report outlines the need for institutional oversight mechanisms for monitoring all human embryonic stem cell research and provides specific guidance regarding the derivation of new stem cell lines. Under the guidelines, certain activities, such as experimenting on human embryos by