The average person is baffled by the stem cell debate: blastocysts, morulae, mitochondria, cytoplasm and dozens of other words are terms that they never even learned properly in high school biology. But you don't need to be a biologist to understand the importance of the ethical controversy which has put stem cells on the front pages of newspapers around the world.
The fundamental issue is the limits of regenerative medicine. This is an exciting new field with enormous potential for repairing damaged organs and body parts with human stem cells. Vast amounts of money and research effort are being invested in it. But like every technological development, it is not ethically neutral. We have to ask where these stem cells come from. If their source is human embryos, there is a serious ethical difficulty. The destruction of embryos for the sake of their stem cells is ethically unacceptable. Human life, even embryonic human life, cannot be sacrificed as a research tool or a medicine.
Normally a skin cell remains as a skin cell all its life. A nerve cell remains as a nerve cell until it dies and so on. Stem cells, however, are cells that can change into many types of cells, such as heart cells, nerve cells, muscle cells, skin cells and so on. They are the trunk or the stem from which the branches (different cell types) develop. The ultimate stem cell are the stem cells in the early embryo because they can develop into every single cell type. Because of this capacity they may prove useful for treatment of some medical conditions as they can be trained in different directions.
Stem cell science is very new and scientists are constantly rewriting the textbooks. At the moment, public discussion is focused on two kinds of stem cells: adult stem cells and embryonic stem cells. Adult stem cells can be taken from body tissue without harming a patient. The word adult means only that the cell is taken from a fully developed organism. This could be an adult, a child, or even from the placenta of a newly-born infant. Embryonic stem cells are removed from early embryos in a process which destroys the embryo. Another type of stem cell is the embryonic germ cell, which are taken from aborted foetuses. These are believed to have almost the same potential as embryonic stem cells.
This backgrounder focuses on the ethics of using embryonic stem cells. Although there are ethical issues with the use of adult stem cells, as with any medical treatment, the use of embryonic stem cells is ethically problematic because it always involves the destruction of an embryo.
Think of stem cell therapy as a kind of microscopic organ transplant. When injected into the body, the cells will travel to damaged tissue and replace or repair it. Amongst the many potential beneficiaries of stem cell therapies are patients with Parkinson's disease, diabetes, spinal cord injuries, heart disease and cancer.
But these developments are a long way off. Even boosters of embryonic stem cell research have conceded that stem cell therapies may be decades away. Diseases are always complex and cures are never simple. Enthusiastic chatter about the theoretical possibility of cures often glosses over years of work in the laboratory to create a therapy which is workable, safe and cost-effective. Optimism must always be tempered with realism.
It is important to stress that the only stem cells that have helped patients so far are adult stem cells. Embryonic stem cell research has not helped a single patient in the entire world. Up til now, it has a zero success rate.
Human embryos are not easy to obtain. At the present time, there are basically three sources: embryos which are left over from IVF treatment, embryos which are created in the laboratory from donor eggs and sperm, or embryos which are cloned from somatic (body) cells.
The embryo is allowed to grow for about five to seven days after fertilization and then it is divided into its component parts. Of course, the embryo is killed in the process. The stem cells are placed in cultures where they multiply rapidly into colonies, or clusters, of cells. The next step is to coax them into becoming the desired cell type (e.g., heart cells, pancreatic cells, brain cells). Programming the cell to differentiate is the focus of intense effort by many researchers around the world. Up to now they have had very limited success.
Some stem cell scientists regard frozen IVF embryos or embryos made from donated eggs and sperm as a useful research tool for investigating the mysteries of embryo development and the mechanisms of genetic diseases. But, at this stage, it is highly unlikely that they can be used for cures. The problem is that the stem cells will not have the same genetic make-up as the patients and will be rejected without using anti-rejection drugs.
So the preferred option, in the view of many scientists, is to create new embryos, via nuclear somatic transfer. This is the same method used to clone Dolly the sheep. That is, human embryos would be deliberately created for the sole purpose of extracting their stem cells, a procedure often billed as "therapeutic cloning". This is a terrible misnomer as it is not therapeutic for the embryo. Some scientists and biotechnology investor predict that cloing embryos will usher in the age of "personalized medicine" -- treatments which are tailor-made for individual patients. This implies, of course, that scientists will be allowed to create "embryo farms" on an industrial scale.
The availability of human eggs limits the potential for "therapeutic" cloning. Eggs are scarce and expensive because few women are willing to experience the pain, inconvenience and physical risk involved in harvesting eggs. If a market develops for eggs, poor women are sure to be exploited -- one reason why a number of feminists oppose "therapeutic" cloning. Therefore, in an escalation of the moral complications associated with stem cell research, some researchers have suggested the possibility of creating hybrid cow-human or rabbit-human embryos with animal eggs.
The only stem cells which have worked in a clinical setting are adult stem cells. In fact, adult stem cells have been used for about 30 years in procedures like bone marrow transplants. In the last few years, scientists have also discovered that adult stem cells exist in many parts of our own body -- the brain, bone marrow, skin and fat and many other locations. The use of these cells has had an impressive head start, although no therapies have yet passed all the hurdles to become a standard clinical treatment.
It used to be thought that embryonic stem cells had more clinical potential than adult stem cells because they are easier to identify, isolate and harvest; because they easier to obtain; because they grow more quickly and easily a laboratory setting; and because they are more "plastic"
Yet all these arguments have proved false. The first two claims are misleading. The challenge of identifying and isolating adult stem cells is being overcome. Several biotech companies have developed proprietary methods to make adult cell isolation and extraction even easier. Although every kind of adult stem cell is present distinct problems, researchers have identified conditions that would allow the multiplication of some kinds by a billion-fold in a few weeks.
The key argument for using stem cells from embryos is they are more "plastic" - that is, they are easier to change into other types of cells. While this claim has some basis the technology is improving so rapidly that it would be rash for anyone to say that adult stem cells will not become a source of all types of somatic cells. The US National Institutes of Health has observed that "the field of stem-cell biology is advancing at an incredible pace with new discoveries being reported in the scientific literature on a weekly basis."
While adult stem cells may never be as completely "plastic" as embryo stem cells they will almost certainly be plastic enough for all practical applications. "These adult tissues don't appear to be as restricted in their fate as we thought they were," said Dennis Steindler, a professor of neuroscience and neurosurgery at the University of Tennessee-Memphis. "In some ways they may not have the same potential as embryonic cells, but once we figure out their molecular genetics, we should be able to coax them into becoming almost anything we want them to be."
Furthermore, some researchers are doing promising work on adult stem cells which appear to share with embryonic stem cells the ability to morph into any type of tissue. Three scientists have recently published peer-reviewed work which indicates that adult stem cells may be as malleable as ESCs. Catherine Verfaillie, of the University of Minnesota, is investigating rare bone marrow stem cells; Alan Mackay-Sim, of Griffith University in Brisbane, is looking at nerve cells in the nose; and Douglas Losardo, of Tufts University, has found that bone marrow differentiated into nine kinds of tissue. Amazing as it may seem to the non-scientist, the anatomy of the human body still has not been fully categorized at a cellular level; there may be other cells which can differentiate into many kinds of tissue.
Media hype suggests that there is no alternative to embryonic stem cell research. But this is a deception propagated by those with a personal and financial interest in the benefits of destructive embryo research. No one has a right to destroy embryos to do this research. We should push ahead with successful and ethical adult stem cell research which involves no destruction of embryos -- and works.
Embryonic stem cell research is the threshold of cloning. As we have already seen, to overcome the problem of immune rejection, the proponents of embryonic stem cell therapies will have to clone embryos. Although nearly all scientists have vowed not to allow these cloned embryos to develop into babies, they certainly could if they were implanted in a womb. Several rogue researchers are already attempting to do this.
Furthermore, nearly all scientists who want to work with embryonic stem cells do not appear to have ethical qualms about so-called reproductive cloning. They simply say that it is unsafe for the cloned child. In its ethical guidelines for stem cell research, the US National Academies of Sciences says (May 2005) merely that "attempts to create a child by means of NT [nuclear transfer, or cloning] are ethically objectionable at this time because, on the basis of experience with other mammalian species, producing one child might require hundreds of pregnancies and many abnormal late-term fetuses could be produced".
At the present time, this is undoubtedly true. But veterinary scientists are working hard to overcome these problems and eventually their research will be applied successfully to the problem of human cloning. When that happens the gossamer-thin ethical objections of stem cell scientists will evaporate. Unless we can put a stop to embryo cloning, the cloning of children is all but certain. The only "bright line" separating therapeutic cloning from reproductive cloning is the intention of the laboratory which creates the embryos. Already a few American couples have publicly appealed to clone their dead children. Lawyers have speculated that if there is a constitutional right to reproduction, there must be a constitutional right to the means to reproduce, even if this means cloning.
The debate over embryo research is not a specifically religious issue. First and foremost it is a human rights debate and a debate about good science versus bad science. In this case, the science which respect human rights has notched up all the successes. Religion sheds light on the stem cell debate by highlighting the importance and scope of human dignity as revealed in the Bible or the Koran. But one does not need to be a believer to see that manipulating and destroying human embryos involves serious ethical issues. Because embryos are an early form of human life, the principles which govern how they are treated will be applied to other stages of human existence. But the fundamental parameters of the debate are set by what constitutes competent ethical science which respects human rights.
The debate over embryonic stem cells is fierce and emotional. But it is important to stress the following points:
Researching on embryos is researching on embryonic persons. It denies the dignity of the human embryo. The human embryo is a distinct, living human being, and is entitled to all the rights and protections as any other human being. Human life begins at conception (or fertilisation). Therefore, the human embryo (regardless of what means by which it is created) should not be treated as a means to an end. It is entitled to life and respect. Once embryonic development commences, a separate and distinct human being exists which should not be used in a purely instrumental fashion. For this reason any technology or proposed therapeutic procedure which involves the destruction of a human embryo should be banned altogether.
Those who argue that a frozen IVF embryo would be destroyed anyway miss the point. The couples who had the embryos created did so for the purpose of implantation, of bringing about life. That surplus embryos exist should be a real concern. It is a scientific mess created by the IVF process. But we should not add to the mess by experimenting on the embryos. We need to find more humane solutions to the ethical dilemma of surplus IVF embryos. Adoption is one possibility. If this is not an option then they can be allowed to die with dignity.
Experimenting upon embryos denies them their fundamental right to be treated with dignity. This can be a hard point to grasp, but an historical example might help to clarify the issues. Not long ago in Austria body parts of hundreds of babies and children were discovered in the office of a famous doctor. He had obtained them during the Nazi period of 1940 to 1944 and used them in his research. When this came to light Austrians were outraged. The authorities did not argue that the children were dead anyway and that valuable knowledge could be obtained from their vital organs. A public interment was attended by huge crowds of mourners. The situation with defenceless embryos is analogous.