The recent derivation of human embryonic stem (ES) cells1 has reignited the debate over human embryo research and has once again highlighted the ethically dubious dichotomy in the US between research that is allowed using federal National Institutes of Health (NIH; Bethesda, MD) funds versus private funds. In the US, the NIH is specifically prohibited from funding any human preimplantation embryo research. Private clinics using private funds, on the other hand, can conduct such research in the US with inconsistent or no ethical oversight. Embryo manipulations that would be broadly condemned as unethical are currently legal if private funds are used. The unusual dichotomy in the US contrasts sharply with the policy of other countries.

In Great Britain, for example, limited human embryo research is allowed, but only with strict, consistent ethical guidelines that apply equally to the public and private sectors.

Because the human ES cells recently described were derived at a public university from embryos produced by in vitro fertilization (IVF), the protocols were carefully reviewed by an institutional review board (IRB), and the ethical implications of human ES cells were examined by a separate ethics advisory committee.

Private funding was used for the derivation of the cells, in a laboratory physically separated from laboratories receiving NIH funding. With current federal law, university researchers who receive NIH funding have often been afraid to pursue privately funded IVF research for fear that a potential intermixing of federal and non-federal funding sources could jeopardize their funding and their jobs. This has had the effect of excluding some of the world's best mammalian embryologists from contributing to the improvement of infertility treatments through IVF.

Why has the derivation of human ES cells so forcefully focused attention once again on human embryo research in the US? The human ES cells recently described were derived from IVF-produced human embryos that were produced for infertility treatment, but were no longer wanted by the couples for implantation and would otherwise have been discarded. The properties of ES cells reflect the properties of the early embryonic cells from which they are derived. ES cells are capable of prolonged, undifferentiated proliferation and yet even after prolonged culture, maintain the developmental potential to form each of the cells of the adult body. Human ES cells are important because they offer an accurate new model for understanding the differentiation of human tissues, offer new strategies for drug development, and promise a range of new transplantation therapies2.

Because of their remarkable developmental potential and proliferative capacity, human ES cells offer a potentially limitless source of specific cell types for transplantation for treating diverse human diseases, including heart disease, Parkinson's disease, juvenile onset diabetes, and leukemia. Many people have family members or close friends who have suffered and died from these diseases. The ban on NIH funding of IVF research has historically harmed primarily those people suffering from infertility; it now harms a much larger segment of society.

Since the birth of the first baby by IVF in 1978, there has been no US federal funding to improve this important method of infertility treatment. Federal regulations (45 CFR 46) established in response to the first IVF birth required that applications for NIH funding first be reviewed and approved by an Ethical Advisory Board (EAB). The EAB, which existed during 1978–1980, considered ethical issues arising from IVF and concluded that federally funded research directed at improving IVF was appropriate if strict guidelines were followed.

However, from 1980 to 1993 no EAB was convened, and thus no NIH funding of IVF research was possible. The NIH Revitalization Act of 1993 removed the requirement for an EAB and once again opened the possibility of NIH funding for IVF research.

In response, the NIH convened the Human Embryo Research Panel to study the ethical issues associated with human embryo research and to advise about areas that were ethically and scientifically acceptable for funding. This panel, composed of ethicists, medical doctors, scientists, and legal scholars completed its report in late 1994. Included in the report are detailed ethical principles and guidelines for preimplantation embryo research. The 1996 and subsequent appropriation bills for the US Department of Health and Human Services (HHS; Washington, DC), which includes the NIH, however, have language expressly forbidding the use of HHS funds for human preimplantation embryo research. Thus, the NIH is currently forbidden from funding the isolation of human ES cells. However, recent HHS legal interpretation of the current law suggests that human ES cells that have already been derived can be funded by NIH, but not until appropriate guidelines are established (for an update see http://www.nih.gov/grants/news.htm ).

The lack of US federal funding for human embryo research reflects contradictory policies that do not advance the public interest. One of the central conclusions of the NIH Human Embryo Research Panel was that: "In the continued absence of federal funding and regulation in this area, preimplantation human embryo research that has been and is being conducted without federal funding and regulation would continue, without consistent ethical and scientific review. It is in the public interest that the availability of federal funding and regulation should provide consistent ethical and scientific review for this area of research. The panel believes that because the preimplantation embryo possesses qualities requiring moral respect, research involving ex utero preimplantation human embryos must be carefully regulated and consistently monitored."3

The US Senate Appropriations Subcommittee on Labor, Health, and Human Service, and Education (Washington, DC), which is responsible for funding HHS, has been conducting a series of hearings on human stem cell research and is reexamining the appropriateness of the human embryo research ban (see http://www.senate.gov/~appropriations/labor/test.htm). The National Bioethics Advisory Commission is also conducting a series of meetings on the ethical implications of human stem cell research (see http://bioethics.gov/cgi-bin/bioeth_counter.pl). The 1994 NIH Human Embryo Research Panel's Recommended Guidelines were the result of an arduous eight month process of public discussion and debate, and the panel specifically addressed human ES cell research.

It is in the public interest that the ban on NIH support of human embryo research be removed, and that the guidelines suggested by the NIH Human Embryo Research Panel be adopted by both the public and private sector.