Understanding Stem Cells part 52

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 conciousness. 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 and 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.

Understanding Stem Cells part 51

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 human stem cells-derived pancreatic cells into a mouse to test their ability to function in a living body). Chimeras are considered essential for advancing stem cells research to viable therapies, since no therapy can be tested in humans without research in animals first,

Understanding Stem Cells part 50

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."

Understanding Stem Cells part 49

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, skin cell) into an egg whose  nucleus has been removed.  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 transplants.

Understanding Stem Cells part 48

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-nonreligious people support embryonic stem cell research, although public opinions seems divided about the creation or use of human blastocysts  solely for research.

Understanding Stem Cells part 47

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 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 of 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 human being only after a few weeks or months of development.

Understanding Stem Cells part 46

Scientists and society as a whole must consider the ethical implications of stem cell research. 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.