inserting stem cells into them, are not permitted. The guidelines also require that all egg, sperm, and blastocyst donations follow appropriate informed consent and confidentiality procedures. Because the ethical and technical questions associated with human embryonic stem cell research are likely to change as science advances, in 2006, the National Academies established a panel of experts to monitor and review scientific developments and changing ethical, legal, and policy issues and to prepare periodic reports to update the guidelines as needed. For more information on the guidelines, please visit www.nationalacademies.org/stemcells. Americans support embryonic stem cell research, although public opinion seems divided about the creation or use of human blastocysts solely for research. The Relationship of Stem Cell Research to Reproductive Cloning Although cloning and stem cell research are often lumped together in the context of ethical debates, the goals and results of the two are very different. The common factor between current attempts at reproductive cloning and stem cell research is a laboratory technique called nuclear transfer. Using nuclear transfer, scientists can create blastocysts containing stem cells that are “clones” of a single adult cell by inserting the genetic material from an adult cell (for example, a skin cell) into an egg whose nucleus has been removed (this process is described in more detail on page 6). Scientists hope that they could derive stem cells from the cells inside such blastocysts and grow replacement tissues that are genetically matched to specific patients, thus offering patients a safer alternative to traditional tissue transplants. Reproductive cloning, such as the process that was used to create Dolly the sheep, also uses the nuclear transfer technique. However, instead of removing the inner cell mass to derive a stem cell line, the blastocyst is implanted into the uterus and allowed to develop fully. In 2002, the National Academies issued the report Scientific and Medical Aspects of Human Reproductive Cloning, which concluded “Human reproductive cloning should not now be practiced. It is dangerous and likely to fail.” The Ethics of Human-Animal Chimeras Chimeras are organisms composed of cells or tissues from more than one individual. Chimeras have been produced for research for many years, but when human and animal cells are mixed in the laboratory, there is a clear need for heightened ethical consideration. Cells from different organisms can be combined either in the early developmental stages (for example, introducing human cells into a mouse blastocyst to observe certain developmental processes) or after an individual is fully developed (for example, implanting 21 ETHICS, moral values, AND U.S. LAW “Human reproductive cloning should not now be practiced. It is dangerous and likely to fail.” —Scientific and Medical Aspects of Human Reproductive Cloning, National Academies Press, 2005 human stem cell-derived pancreatic cells into a mouse to test their ability to function in a living body). Chimeras are considered essential for advancing stem cell research to viable therapies, since no therapy can be tested in humans without research in animals first. Some people believe that the creation of chimeras involving human cells for medical research is morally acceptable as long as the chimera has no level of human consciousness. Therefore, research in which it is possible for human stem cells to produce part of an animal’s brain should be conducted with great care. The National Academies’ guidelines prohibit the introduction of human cells into the blastocyst of a non-human primate, or the introduction of any animal or human cells into a human blastocyst. The guidelines also prohibit the breeding of human-animal chimeras in the unlikely event that any human genetic material would be contained in their reproductive cells. ETHICS, MORAL VALUES, AND U.S. LAW Is it legal? Currently, all forms of stem cell research in the U.S. are legal at the federal level. That is, it is not illegal to make or work with new embryonic stem cell lines. However, the use of federal funds for human embryonic stem cell research is restricted to the cell lines that were available as of August 9, 2001. Therefore, the derivation of new embryonic stem cell lines can only occur when scientists are working with non-federal funding. Some states and private foundations have been supporting this work. Some requirements of federal law, such as human subjects protections, apply to state- and privately funded stem cell research. For a complete discussion of the mechanisms for oversight of stem cell research, see the National Academies’ report Guidelines for Human Embryonic Stem Cell Research. It is legal to conduct research using blastocysts and to derive new cell lines in most states, with some exceptions. Because stem cell legislation is an area of active debate, please visit the National Conference of State Legislatures at http://www.ncsl.org/programs/health/genetics/embfet.htm to learn about the laws in a particular state. ABOUT THE NATIONAL ACADEMIES The National Academies are private, nonprofit organizations that were set up to provide independent scientific and technological advice to the U.S. government and nation. The National Academies includes