The issue of research involving stem cells derived from human embryos is back in the news after a federal judge clarified that the government cannot use federal funds for such immoral research. Although the debate has been ongoing for almost ten years, the complexity of the issue and the peculiar terminology used often prevents many citizens from developing a fully informed opinion on the matter. To help, in some small way, redress that problem, I’ve compiled a brief primer, a “least you need to know” guide, that helps clarify and explain the questions most frequently asked about stem cell policy.

To those unfamiliar with the topic, this should provide brief non-technical answers to many of the important questions surrounding the policy. For those who are well versed in the controversy, I hope this will be a useful reference source to help you explain the issue to others.

What are stem cells?

The term stem cells refers to a diverse group of primitive cells that are themselves relatively undifferentiated and unspecialized. These cells are multipotent, meaning they can give rise to several other differentiated and specialized cells of the body (for example, liver cells, kidney cells, brain cells). All specialized cells arise originally from stem cells, and ultimately from a small number of embryonic cells that appear during the first few days of human development.

How are stem cells different than other types of cells?

Stem cells have two unique characteristics: (1) an almost unlimited capacity for self-renewal (they can theoretically divide without limit to replenish other cells for as long as the person is alive) and (2) they retain the potential to produce differentiated and specialized cell types. As stem cells within a developing human embryo differentiate within the cell, their capacity to diversify generally becomes more limited and their ability to generate many differentiated cell types also becomes more restricted.

Why are stem cells so important to research?

Stem cells are of interest to both scientific and medical research. First, stem cells provide a valuable tool for studying both normal and abnormal cellular processes. By learning how stem cells differentiate and become specialized, scientists hope to gain a better understanding of how cells in general work and what can go wrong. Second, stem cells may prove to be an indispensable source of transplantable cells and tissues for repair and regeneration. If stem cells can used to produce new and differentiated cells that are damaged because of disease (e.g., Parkinsons) or injury (e.g., spinal cord damage), it would transform regenerative medicine.

What are embryonic stem cells?

Embryonic stem cells (ESCs) are stem cells taken from from the inner cell mass of a blastocyst, a preimplantation embryo of about 150 cells. (Embryos are humans in the stage of development between fertilization and the end of the eighth week of gestation whereupon it it referred to as a fetus until the time of birth.)

Where do the embryos for ESC come from?

Currently, all embryonic stem cell lines have been derived from “spare” embryos created from in vitro fertilization (IVF) (i.e., embryos that have been conceived by a combination of egg and sperm occurring outside the body). However, because there are not enough embryos in existence to carry out the research, some scientists have been pushing for the use of human cloning (somatic cell nuclear transfer) to create the embryos that will then be killed and harvested for their cells.

What are adult stem cells?

The term adult stem cells simply refers to any non-embryonic stem cell, whether taken from a fetus, a child, or an adult. Adult stem cells are also referred to as somatic stem cells.

What is a stem cell “line”?

A stem cell line is a stem cell culture that can be grown indefinitely in the laboratory.

Why is there a controversy over ESC research?

The process of obtaining stem cells leads to the destruction of the human embryo from which the cells are taken. For those who believe that life begins at conception, embryo destruction is immoral even when it leads to beneficial research. Even those who do not believe that human embryos are deserving of full moral status worry about what the effects of normalizing such practices may have on society.

Advocates of ESC research, however, argue that it is unethical to impede potential advances that could heal disease and relieve the suffering of fully developed human beings. They believe that the moral status of a 150-to-200-cell early human embryo should not take precedence over scientific inquiry.

Didn’t the Bush administration ban funding of ESC?

No, but the Congress implemented its own ban. In 1995, Congress attached language to an appropriations bill prohibiting the use of any federal funds for research that destroys or seriously endangers human embryos, or creates them for research purposes. This provision, known as the Dickey Amendment , has been attached to the Health and Human Services appropriations bill each year since 1996. This law only prohibits federal funding of such research and does not affect either private funding efforts or private research that involves the destruction of embryos.

If the Dickey Amendment banned funding of embryo destruction, how was Bush able to allow such research to be federally funded?

In 1999, the General Counsel of the Department of Health and Human Services argued that the wording of the law might permit an interpretation under which human embryonic stem cell research could be funded. If embryos were first destroyed by researchers supported by private funding, then subsequent research employing the derived embryonic stem cells might be considered eligible for federal funding. The research would follow the prior destruction of human embryos but would not itself involve that destruction.

President Bush, seeking to find a way to fulfill the letter if not the spirit of the law, instituted a policy that made it possible to use taxpayer funding for research conducted on preexisting ESC lines, but would prohibit the funding of any lines created after August 9, 2001, the date of the policy’s announcement.

However, U.S. District Judge Royce Lambert recently rejected the government’s attempt to distinguish between the destruction of the embryo and research on the destroyed embryo as distinct “pieces of research”—one ineligible for funding and one eligible. They “cannot be separated,” the judge said. “ESC research is clearly research in which an embryo is destroyed,” Lamberth wrote. “To conduct ESC research, ESCs must be derived from an embryo. The process of deriving ESCs from an embryo results in the destruction of the embryo. Thus, ESC research necessarily depends upon the destruction of a human embryo.”

Since the government doesn’t prohibit private funding why does it matter if tax dollars are used for the research?

Besides making and enforcing law, the federal government is a major distributor of resources. When the decision to fund an activity is made, it is an official declaration of national support for an activity. When something is done with public funding, it is done, so to speak, in the name of the country, with its blessing and encouragement. Because there is no general consensus on the morality of ESC research, the federal government had chosen—prior to Obama’s inauguration—to withhold its full support even though it does not wish to entirely prohibit the activity.

Has embryonic stem cell research ever resulted in therapeutic treatments?


Has adult stem cell research ever resulted in therapeutic treatments?

Yes, currently there are 73 treatments that have been derived from adult stem cells.

Are there any restrictions on adult stem cell research?

No. Because there are no moral issues surrounding that type of research, adult stem cells are available for funding. In fact, over the past ten years the NIH has allocated hundreds of millions of dollars to fund adult stem cell research.

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