The Linacre Centre for Healthcare Ethics
Summary
1. Introduction
1.1 Stem cells
1.2 Embryonic stem cells
1.3 Cloning
2. Scientific issues
2.1 Adult stem cells
2.2 Embryonic stem cells
2.3 Cloning for birth
2.4 Cloning for transplantation
3. Status of thehuman embryo
3.1 What is a human moral subject?
3.2 When does the human individual begin?
3.2a Fertilisation
3.2b The embryo and its placenta
3.2c Identical twinning
3.3 Do all human beings have full moral status?
3.3a Human rights
3.3b Human embryos
4. Respecting theembryo
4.1 Rights of the embryo
4.2 Research on 'spare' IVF embryos
4.3 IVF for research
4.4 Cloning for research
4.5 Conscience and complicity
4.6 Cloning for birth
5. Public policy
5.1 General principles
5.2 Benefits and alternatives
5.3 Unacceptable consequences
5.4 Recommendations
6. Responses toquestions
Summary
S.1 There are scientific aspects of cloning and stem cell research which needto be clarified before ethical questions are posed. In particular, it seemsthat research on adult stem cells is comparably advanced to and perhaps morepromising than research on embryonic stem cells. Further, the results ofattempting to clone non-human animals cast serious doubt on the safety ofcloning for transplantation, as well as cloning for birth (see sections1.1.1-2.4.1).
S.2 Human beings are animals (of a special sort) who begin to exist when theindividual organism begins to exist. The universal terminus a quo indevelopmental biology is fertilisation. The development of the placenta andother foetal organs does not undermine the significance of fertilization as thenormal beginning of the human organism, and neither does the phenomenon ofidentical twinning, if this is correctly understood (see sections3.1.1-3.2c.6).
S.3 The basis of the concept of human rights is that there is a minimum respectwhich is due to all human beings simply in virtue of their being human. Thisrepresents the rejection of the possibility of a natural human underclass(consisting of slaves, the disabled, women, children, or those of `lesser'races). The humanity of embryonic human beings entitles them also to a minimumhuman respect, despite the evident differences between human embryos and olderhuman beings (see sections 3.3a.1-3.3b.7).
S.4 The human rights of the embryo include the right not to be attacked, usedor commercialized, and the right to a certain care from the genetic parents. Itis irresponsible to allow one's genetic material to be used to create an embryowho has no chance of implantation. IVF for research and cloning for researchare wrong for similar reasons, whereas cloning for birth is wrong for otherreasons (see sections 4.1.1-4.6.7).
S.5 The Helsinki Declaration on Medical Research Involving Human Subjectscondemns research which is without the consent of the subject, harmful to thesubject or which subordinates the interests of the subject to the interests ofscience and society. In cases of genuine doubt concerning the humanity of thesubject one should err on the side of caution. A significant body of scholarlyopinion to the effect that embryos are human beings constitutes a reasonabledoubt concerning their supposed subhuman status. Human embryos should thereforebe protected by law (5.1.1-7).
S.6 Human cloning for research and a major expansion of research on IVF embryosare being permitted in the face of international condemnation when it is farfrom evident that there is an urgent necessity to justify such dramatic moves.Such practices are likely to lead to cloning for birth, to further erosion ofpublic confidence in the ethics of scientific research, and to an invidiouspromotion of treatments which many patients will regard as unconscionable.Cloning should be prevented before the regulations come into effect(5.2.1-5.4.1).
1. Introduction
1.1 Stem cells
1.1.1 Stem cells are versatile cells in the body which areable both to reproduce themselves and to produce more specialized cells. Assuch, they are of great potential value in repairing and regenerating damagedcells and tissue. Many conditions are currently or potentially treatable withthe use of stem cells, including Alzheimer's, Parkinson's, heart disease,stroke and diabetes.
1.1.2 Stem cells can be obtained from various sources. They can be obtainedfrom the early human embryo, from the older human embryo or foetus, from thenewborn baby (e.g. from the umbilical cord), from the older child and from theadult. As the individual develops, it is thought that stem cells become morecommitted to a particular destination in the body; however, some degree offlexibility appears to be retained. (We will be looking in the next section(2.1) at the clinical potential of adult versus embryonic cells.)
1.2 Embryonic stem cells
1.2.1 Embryonic stem cells can be obtained from the humanembryo or foetus during or after an abortion, or after a miscarriage. They canalso be obtained from the early human embryo after in vitro fertilisation (IVF)or similar procedures. The IVF embryo may be `spare', i.e. surplus tothe infertile couple's requirements. Alternatively, the embryo may bespecifically created for experimental use.
1.3 Cloning
1.3.1 Embryos may very soon be created for experimental useby means of cloning. In this procedure, the nucleus of an unfertilised ovum isreplaced by the nucleus of a body cell from an existing human being. The ovumis then stimulated to create an embryo. As the nucleus contains almost all ofthe cell's genetic material, the embryo created is the clone or twin of thehuman being from whom the nucleus was taken, and could be used as a source ofstem cells for research and eventual transplantation.
1.3.2 Cloning for research is sometimes described as therapeutic as opposed toreproductive cloning. In `reproductive' cloning, the clone is transferred tothe body of a woman and allowed to go to term. It should be noted that thecloning procedure itself is identical for `reproductive' and `therapeutic'cloning: the only difference lies in the purpose for which the clone would becreated.
1.3.3 The terms `reproductive' and`therapeutic' in this context are misleading.(1) `Therapeutic' cloning is nottherapeutic for the clone, who will die in the course of its cells being takenwhen it is 5-7 days old. Such cloning is, moreover, reproductive, sinceit involves the creation of an embryo, although this embryo will not survive tothe point of being born. Supporters of cloning have conceded that the cloneembryo is a human organism: an early human life.
1.3.4 In this Submission, we will be referring not to`therapeutic' and `reproductive' cloning, but to cloning for birth, and cloningfor research/transplantation.
2. Scientific issues
2.1 Adult stem cells
2.1.1 Until recently, it was thought that stem cells could rarely be found inadult tissue. However, this view has been conclusively disproved. The last twelvemonths have seen an explosion of information on adult stem cells (the term isoften used to include stem cells from, for example, newborn babies). Adult stemcells have, in fact, been given to patients for decades in the course of bonemarrow transplants, and new trials on patients using adult stem cells have hadpositive results.
2.1.2 It is clearly best if the cells used intransplantation can be taken from the patient him- or herself, to avoidrejection by the body. While embryonic cells have been proposed as a means ofavoiding rejection problems, even early embryonic cells have surface moleculeswhich can cause an immune response.(2) Supporters and opponents of embryonicstem cell research are in agreement that the ultimate goal should be to use thepatient's own cells.
2.1.3 There are various ways in which adult cells canbe used. They can be taken from the patient, or a donor, and used without beingmodified, as in the case of bone marrow transplants for patients with cancer.Alternatively, stem cells from the patient can be subjected to gene therapybefore being re-introduced, as in the case of children who were treatedrecently for Severe Combined Immune Deficiency.(3)
2.1.4 Stem cells can be induced to carry out a new rolein the body, as when a patient with heart disease was given stem cells frommuscle in his leg, which then formed a different kind of muscle in his heart.(4)It is known that adult bone marrow cells are particularly versatile, and canproduce bone, cartilage, tendon, muscle, fat, liver and neural cells. Neuralstem cells can also form other cell types, such as blood and muscle cells.
2.1.5 Finally, there are ways of treating stem cellswhile they are still in the body of the subject. In animal studies, positiveresults have been obtained by adding the proper growth signal to the injuredbrains of rats, so that their own stem cells could proliferate.(5)
2.1.6 Treatments of human patients using adult cellsare already yielding results. Successful treatments have been carried out onchildren with cartilage defects,(6) patients with corneal scarring,(7) andpatients with lupus,(8) systemic sclerosis(9) and rheumatoid arthritis.(10) Anumber of cancers have been successfully treated using adult cells, includingmetastatic retinoblastoma, which has a poor prognosis with conventionaltreatments.(11)
2.2 Embryonic stem cells
2.2.1 How do these achievements using adult cellscompare with those made using embryonic cells? It should be noted that cellsfrom early embryos have not so far been used on patients, and appear toounspecialised to control, unless modified in some way.(12) We are some yearsaway from any treatment using early embryonic cells.
2.2.2 Where stem cells from foetuses have beentransplanted into patients along with other tissue the results have not beenaltogether positive. Even foetal cells can be difficult to control, and it isfeared that embryonic stem cell transplants could give rise to cancer. In onecase, a man with Parkinson's died after a transplant of foetal cells; it waslater found that these cells had given rise to bone, skin and hair in thepatient's brain.(13)
2.2.3 A recent clinical trial did find some improvementin younger Parkinson's patients (those aged 60 or less). However, in 15% ofthose treated the patient developed permanent uncontrollable movements such aswrithing, head-jerking and constant chewing.(14) One patient now has to betube-fed, so severe are his symptoms.
2.2.4 In animal experiments, there have been somefavourable results using embryonic cells. However, there are technical problemsinvolved in keeping human embryonic stem cells alive, and in making themdifferentiate along the right lines. A trial in which cells from human embryoswere transplanted into rats found that these cells did not readilydifferentiate into brain cells. Instead, they stayed together in a disorganizedcluster, and nearby cells began to die.(15)
2.2.5 While it is too early to say whether embryonic oradult stem cells will ultimately prove more effective, there is more currentevidence of usefulness in the case of adult cells. Statements to the contrarymay owe more to external pressures - political or commercial - than to thescientific data. To quote the journal Science in December 2000, `thehuman embryonic stem cells and fetal germ cells that made headlines in November1998 because they can, in theory, develop into any cell type have so farproduced relatively modest results. Only a few papers and meeting reports haveemerged from the handful of labs that work with human pluripotent cells.' (16)
2.3 Cloning for birth
2.3.1 Cloning for birth has been carried out in various species of mammal,including sheep, cows, mice, pigs and goats. However, it is very difficult toproduce a healthy animal by cloning. Problems arise at every point: inproducing embryos by cell nuclear replacement, in bringing these embryos toterm, and in obtaining healthy live-born offspring. There is a high rate ofmiscarriage of clones, throughout the period of gestation, and a high rate ofneonatal death. Major fluid retention in the gestating mother has also beenobserved.
2.3.2 Abnormalities in clones include developmental delays, heart and lungdefects, malfunctioning immune systems, and excessive size. Genetic errors inthe clone can cause unpredictable problems at any stage. Some mouse clones,after growing to the equivalent age in humans of thirty, suddenly become obese.
2.3.3 Despite these problems, there are those who wish to carry out cloning forbirth in human beings. Fertility specialists Panos Zavos and Severino Antinoriplan to clone for birth within the next two years. Zavos claims it will bepossible to identify abnormalities at the embryo stage, so that abnormalembryos can be discarded. However, experts in animal cloning have suggestedthat this cannot be done, since there is no test for determining whether genesin the embryo have been properly reprogrammed.
2.4 Cloning for transplantation
2.4.1 The high rate of serious abnormality inanimal clones gives us reason to fear the effect on patients of transplantinginto them genetically abnormal cells from an embryonic clone. In general,embryonic cells are unstable and difficult to control because of theirpluripotency. Cells from a cloned embryo, prone to genetic abnormality, raisestill more difficulties. In any case, the great expense involved in cloning,and the need for a large number of human eggs, would be major impediments toits clinical use.(17)
3. Status of the human embryo
3.1 What is a human moral subject?
3.1.1 Morality and law are concerned with the respect that is due to human beings as moral subjects. People are not reducible to the sum of their physical parts or their biological drives. Mature and competent human beings can make decisions for themselves, for which they are held responsible both morally and legally. Furthermore, all human beings are members of the human community, whether or not they have come to full maturity, and all share a common humanity.
3.1.2 No human being is to be thought of as a mere physical object or a mere animal, for all possess a common dignity or significance that is not shared with any other animal.(18) However, it is also important to stress that human beings are animals - of a particular sort. We should not think that the real person is a ghostly spirit inside the head (the mind or consciousness) or a demon who has taken possession of a body - as though the living human body were one thing and the person were something else. This would degrade the human significance of the body and undermine the conviviality and bodily communication that help to constitute the human world.
3.1.3 The Greeks defined a human being as a `rational animal' and this seems to capture something of the essence of a human being, as long as we are careful not to define `rational' in too narrow a fashio
