Despite this diversity of religious and philosophical views, it is well known that, over the past eight years, the Bush administration took an embryo protectionist position.It consequently put in place legislature, in the form of an executive order, that restricted federal funding for h ES cell research to just those h ES cell lines that were in existence on August 9, 2001.
In the near future, as the stem cell field progresses closer to the clinic, additional ethical issues are likely to arise concerning the clinical translation of basic stem cell knowledge into reasonably safe, effective, and accessible patient therapies.
This Review summarizes these and other bioethical issues of the past, present, and future of stem cell research.
Since this technique sought to preserve the ability of the donor to implant and develop to birth, it theoretically could allow for the banking of autologous h ES cell lines for children born from biopsied ex-corporeal embryos.
In the other study (), Alexander Meissner and Rudolf Jaenisch developed in mice a variation of somatic cell nuclear transfer (SCNT), a technique whereby the DNA of an unfertilized egg is replaced by the DNA of a somatic cell, by blocking the action of a gene (caudal type homeobox 2 [Cdx2]) that enables the developing embryo to implant into the uterus.
Although there are interesting ethical issues surrounding the collection and use of somatic (adult) stem cells from aborted fetuses and umbilical cord blood, the most intense controversy to date has focused on the source of human embryonic stem (h ES) cells.
At present, new ethical issues are beginning to emerge around the derivation and use of other h ES cell–like stem cells that have the capacity to differentiate into all types of human tissue.It is safe to say that, despite a host of other concerns about where science was leading us in the future, the ethical discourse over stem cell research for the past decade has been characterized predominantly by the debate over embryo destruction.In the United States, for example, a sizable minority has objected to the fact that five-day-old preimplantation human embryos are destroyed in the process of harvesting their stem cells ().Other sources of h ES cell research funding, notably state funding initiatives such as those in California, New York, and Massachusetts, began to emerge to help fill the void left by the Bush policy.In order to bypass the ethical controversy surrounding embryo destruction and to help advance stem cell science, the President’s Council on Bioethics recommended in 2005 that “alternative sources” of pluripotent stem cells be pursued that do not involve the destruction of or harm to human embryos ().Each of these issues is discussed as I summarize the past, present, and future bioethical issues in stem cell research.The main bioethical issues associated with human stem cells involve their derivation and use for research.Two studies () published soon thereafter in Nature pursued two of the President’s Council’s suggested alternative stem cell sources — live embryo biopsy and bioengineered embryo-like artifacts.In one of these studies (), Robert Lanza and colleagues succeeded in deriving mouse embryonic stem cells from single blastomeres separated from eight-cell-stage mouse embryos.Scientists were quick to point out that the h ES cell lines on the federal registry were insufficient to support the full range of stem cell research since they lacked genetic diversity, were beginning to accrue genetic mutations, and had been grown on mouse feeder layers (which introduce the threat of animal viruses).Scientists therefore believed that h ES cell lines other than those on the federal registry would have to be studied.