Discussion: a response

Brief descriptions of the contributors are provided at the end of the discussion.

John Polkinghorne: Ethical issues

In relation to the ethical propriety of stem cell research, the critical issue is that of whether an early embryo already has the full moral status of a human being. If that were to be the case, it would be very widely agreed that nothing should be done to it except for its own good, and so the extraction of stem cells would be no more ethically permissible than would be the removal of a kidney without consent from an adult person. However, many of us follow the Warnock Report in assigning deep moral respect to the very early embryo (less than 14 days of growth) on the basis of its human potentiality, without equating it to a fully human being. If that is the case, the instrumental use of early embryos for serious therapeutic purposes not attainable through a non-embryonic route, becomes an ethical possibility to be considered on a case by case basis. It is worth noting that in the history of Christian thought, this developmental view of the embryo has had significant support, including the opinion of St. Thomas Aquinas (influenced by Aristotelian biology).

The use of cell nuclear replacement techniques offers an important possibility of being able to treat severe mitochondrial disease. Moreover, it does not involve cloning, since the nucleus of the fertilised egg to which the technique would be applied would be as genetically unique as any other product of fertilisation. However, the procedure would involve germ-line therapy. Admittedly this would be a 'mild' case of such therapy, but one would need to think very carefully about all the implications of even this modest breach of the currently accepted moratorium on human germ-line genetic engineering.

Azim Surani: Issues of practical implementation

As a developmental biologist I would like to make four main points. First, it does not seem to me very likely that therapeutic cloning will prove to be a practical option in the clinic. First, the procedure will need very large numbers of oocytes. One could think of harvesting immature fetal ovaries when available during abortions for harvesting immature oocytes that could be matured in vitro etc. to overcome this problem. Some have suggested using oocytes from other mammalian species but this may also not work very efficiently. Even if all these problems are surmountable, there will be a need to establish people with very specialized skills to carry out micromanipulation and grow up the blastocysts and derive embryonic stem (ES) cells. Then start to differentiate them along specific cell type required by a patient. This seems like a very tall order. I do however favour the idea that therapeutic cloning research should be allowed, as it may be informative concerning how somatic nuclei get reprogrammed. This information together with animal experiments will allow us to take a more mechanistic approach to this whole area in the future (see 3 below).

Second, people have often argued about imprints being very crucial to stem cell therapy. I agree up to a point but I think that this view may be exaggerated. Imprints are important during development but here we are talking about introducing differentiated cell types into adults (and possibly into children, which may need some care). If differentiated cells from ES cells are well characterized, have the necessary properties of adult differentiated cells and are free of pluripotent stem cells, I would think that they would probably be acceptable to use in patients.

Third, the approach that I think would work well and at the same time raise fewer ethical concerns is to design protocols by which differentiated somatic cells can be dedifferentiated that do not require the use of oocytes. Some research is progressing along these lines although it is at an early stage. This approach will need a very detailed understanding of how to reprogramme genomes. Detailed understanding of the epigenetic mechanisms from all areas of research would provide the mechanistic underpinning to this approach. I also prefer this approach because the procedure would be based on knowledge of the underlying mechanisms involved and this mechanistic underpinning would ensure both an efficient and safe approach. While there is an emphasis on the intrinsic mechanisms involved in reprogramming of the genome, we should also learn about how environmental signals can induce epigenetic changes in target cells.

Fourth, when we have reprogrammed cells, we will still need to learn many tricks to differentiate them appropriately. Here, we could use knowledge from developmental biology and embryology and try to use the information from what happens in vivo to apply to the situation in vitro. It is possible that the in vitro system may not always recapitulate exactly what happens in vivo.

Derek Burke: Realizable goals

I was much impressed by the comments of Professor Surani about the substantial amount of work that still remains to be done before current research in stem cells is clinically applicable. I had formed the impression from what I have read from the proposals put to Parliament and from groups such as the Parkinson's Society, that we were close to clinical use, but if this is not so, then we are in real danger of overselling this new technology, and damaging its promise. This is not new: we did it over biotechnology in the early Eighties when some companies, and I was in one, were desperate to raise new money from the Venture Capital market and it is common today to overstate the likely commercial outcome of current research. The reasons for doing this are understandable, but I suggest that the overall public consequences are serious. It is, I think, very important that we do not risk such an oversell, with the inevitable backlash, with this new technology. It means telling the public as it really is.

Beleil Tanweer: An Islamic perspective

For many couples there are no set cures for their infertility causes to date. But, while cures are being revealed to us by Allah (God), there are many options for couples to be blessed with successful pregnancies. Some Muslims, in Sudan as well as in many other Islamic countries, are of the opinion that a couple that faces infertility should simply accept what Allah has given them. They do not recognize that infertility is a "disease" in which a Muslim should seek the cure. As Muslims we have a duty to seek treatment for any disease and infertility should not be viewed any differently.

In Sudan, the first IVF centre, Khartoum Fertility Centre, was established in January 2000. The centre provides a comprehensive range of fertility services such as Intra-Uterine Insemination (IUI), In vitro Fertilization (IVF), Embryo Transfer (ET), Intracytoplasmic Sperm Injection (ICSI) and Embryo Cryopreservation Techniques. One of the most common artificial insemination techniques is In vitro Fertilisation (IVF).

However, there are several aspects that should be considered from an Islamic point of view. The issue of using donor eggs or donor sperm is the most important point. Lineage is a much protected aspect in Islam. Since Sudan is an Islamic country, the use of sperm of a donor is not lawful for any woman unless she is married to the man giving the sperm. As is the case with donor eggs and a rented womb, these are not lawful for a man unless they come from his wife. That is because the same outcome occurs when children are born from zina (adultery, fornication).

As new medical techniques are being discovered, it brings constant questions for Muslims to address. One such recent question for many is the use of embryonic stem cell in research. It is hoped that the use of embryonic stem cells will cure such things as Parkinson's, Alzheimer's, heart disease and stroke as well as repairing spinal injuries.

In Islam, the research on embryonic stem cells has caused many debates from the scientific use of such cells to the moral questions surrounding the research: Is an embryo at such an early stage considered a human life in Islam? If so, is allowing the otherwise unused embryo to die a form of abortion? If it is not seen as a form of abortion and the embryo is not considered a form of human life, then why are there such objections to embryonic stem cell research?

There are many Islamic groups with different opinions to all three questions. The majority, however, do not authorize growing human embryos regardless of the motive and at present, there is no agreement on embryonic stem cells use.

Michael Harris: On 'being' human

As a Christian, a medical student and a scientist, I have a deep interest in the scientific, medical and ethical aspects of stem cell technology. For this reason, I was very pleased to be invited to the dinner, and was looking forward to learning much about this subject from the talk by Lord Walton and the subsequent discussion.

My impression is that the issue at the heart of this whole area is the status of the embryo -that is, at what point does the embryo have 'being'? With regards to this, I was interested to hear of the concept of individuation and how it underlies the present laws concerning the length of time that it is permitted to experiment on embryos. My concern is, are we assigning personhood to an embryo based on a human viewpoint (as, it appears, we are)? If so, is this correct or is it supremely arrogant of us as creatures to be doing this? Should we rather be taking our assignation of personhood from that which has been divinely attributed? This, of course, opens up a raft of further questions depending on one's philosophical viewpoint!

Whilst, academically, I am excited by the prospect of stem cell research and what it will tell us about developmental processes and what it might mean for therapy, I am concerned that we might be robbing Peter to pay Paul. Are we 'taking' life to 'give' it? If so, is there a point at which we have to say, 'Enough'? I thought that, perhaps, as a doctor, the best treatment I could offer to some of my patients would be compassion. Perhaps this can be overlooked in our quest to cure every disease. I was interested, too, to hear the notes of caution sounded by several at the discussion about overselling the possibilities of stem cell technology.

My impression is that we should tread very carefully in this profoundly deep area that goes to the roots of our being as humans. I believe, though, that continual dialogue, such as that which we had this evening, is needed on these issues and that this is an important way to institute and maintain the necessary checks and balances.

Gerald Gleeson: The status of the embryo

Human actions depend on human choices, choices or proposals about how to pursue our goals. Ethics evaluates the right and wrong ways (or "means") of pursuing our (typically) good goals (or "ends") such as the advance of medicine.

While stem cells can be obtained from several sources, the preferred source for many scientists is a human embryo in the earliest stage of development. The central ethical question raised by this proposal is whether destructive experimentation on human embryos for the sake of medical progress in the long term is morally permissible.

(I say "in the long term" because it is clear that the development of therapies is a long way off, and that any therapy that might one day be developed will have only a very remote connection to the many embryos that were destroyed in the course of developing it. There is no meaningful sense in which current research and experimentation is linked to direct, tangible benefits to any living human being - despite the frequent claims to this effect. Thus current research applications typically concern gene function, toxicology, and drug screening.)

The resolution of this ethical question turns on the resolution of two more basic issues:

1. Whether it is right to separate human reproduction from the context of marriage and the sexual intimacy of spouses. (The Roman Catholic Church's teaching opposes this separation.)
2. Whether every human embryo deserves unconditional respect as a member of the human species, as "one of us", such that a developing embryo (whether specially produced for research purposes or whether "spare" to other programmes like in vitro fertilisation, IVF) should never be used as a means to an end, no matter how good the end may be.

I focus here on the second issue - why I believe the destruction of human embryos is morally wrong.

Prima facie, the biological life of a human being continues from conception to death. My life and your life is continuous with the life that began at fertilisation. And the life that begins at fertilisation will - provided it is supported - develop into a human being just like me and you. (Identical twins might say that they had the same human beginning.)

Respect for embryonic human life is the correlative of respect for ourselves as embodied, living beings. Respect for ourselves includes respect for the way our lives began, and this in turn requires respect for those whose lives would be cut short if, as embryos, they were used as the subjects of scientific experimentation. Human embryos have a right to live, just as you and I do.

Is 'the conceptus' just a collection of cells that happen to be held together by the zona pellucida? No - because I believe there is good biological evidence that the conceptus acts "as a single being", as its cells influence one another, and as it regulates its development and 'communicates' with the mother. The first cleavage is best understood as the result of inte-grated activity on the part of the organism that the zygote is, as it begins its self-development. The unity of the conceptus is also evidenced by the fact that even the angle at which the sperm initially penetrates the ovum is relevant to the subsequent positioning of the "primitive streak" and the separation between inner cell mass and trophoblast.

The totipotentiality of early embryonic cells is often invoked to show that the conceptus is not an individual entity. However, this totipotentiality is primarily directed towards the growth and self-regulation of the embryo itself (e.g. allowing the embryo to make up for any 'lost' cells). The potential these cells have to become a separate individual human is secondary and conditional, a "side-effect" dependent for its actualisation on quite external factors (such as those provided in a laboratory). The fact that cells removed from the embryonic cluster may (then or still) be totipotent or pluripotent doesn't show that they were not (previously and normally) an integral part of an individual embryo.

I am thus sceptical about the proposed ethical distinction between our responsibilities towards a 12 day old embryo and our responsibilities towards an embryo that has implanted in the uterus. I don't hear many scientists in this field positing such a distinction - and I suspect that if, for the purposes of research, it were deemed necessary to use post-implantation embryos, there would be strong pressure for the law to be changed to permit this.

In other words, I think the current legal position - allowing destructive experimentation prior to day 14 - is a pragmatic compromise based on a dubious biological distinction, a compromise that scientists will invoke only for as long as it suits their research goals.

This brings me to the question of the motivation out of which choices are made. Clearly, these are exciting times for embryology and molecular biology. The "logic'" - i.e. the excitement - of the scientific motivation is to want to know more and more and to attain mastery over our world and our own human nature. It is extremely difficult for any scientist - qua scientist - to stop and acknowledge limits on what we may or should do, limits we transgress at the risk of damaging our humanity. I believe that unconditional respect for human life in the earliest stage of development is one such limit.

To be sure, individual scientists may set limits for themselves - e.g. refusing to undertake reproductive human cloning - but there is nothing in the logic of science itself that demands such a limit. Does anyone seriously doubt that reproductive human cloning will not be undertaken one day? (Or, indeed, that it is not being currently attempted somewhere in the world?)

My conclusion: we should pursue ways of studying stem cells that do not involve the creation and destruction of human embryos.

Further reading: Mark Johnson, "Delayed Hominization", Theological Studies 56 (1995) 743-763

Timothy Russ: Clarifications

Dinner/discussion attendees

Lord and Lady Walton, former Warden, Green College, Oxford, Professor of Neurology and Dean of Medicine, University of Newcastle (see the earlier brief biography).

Dr Denis Alexander, Fellow, Chairman, Molecular Immunology, Babraham Institute, ed. Science and Christian Belief, national committee of Chrisitians in Science.

Professor Derek Burke CBE, Honorary Fellow, molecular biologist, broadcaster, former Vice-Chancellor, University of East Anglia, senior advisor to numerous Select Committees, government departments and European Union

Dr Stephen Charnock-Jones, University Lecturer in Department of Obstetrics and Gynaecology, molecular biologist, research on angiogenesis in pregnancy

Rev Dr Geoffrey Cook, Vice-Master, Department of Anatomy, MRC External staff, biochemist working on neural growth cones, deacon Roman Catholic Church

Rev Dr Gerald Gleeson, Visiting Scholar, University of Melbourne, research into applied ethics, priest Roman Catholic Church

Mike Harris, medical student, vacation work in the Department of Obstetrics and Gynaecology

Professor Sir Brian Heap FRS, Master, Vice-President Royal Society, reproductive biologist, Department of Health Expert Group on Cloning, Nuffield Council on Bioethics

Professor Martin Johnson, Department of Anatomy, reproductive biologist and research in developmental biology, bioehtics, author of textbooks on Reproduction

Dr Sue Metcalfe, Bye Fellow, transplantation immunologist, School of Clinical Medicine, Addenbrooke's Hospital

Dr Roger Pedersen, Department of Surgery, School of Clinical Medicine, developmental biologist, human stem cells, University of California, San Francisco, brain gain

Sir Keith Peters FRS, Regius Professor of Physic, formerly Professor of Medicine and director of Royal Postgraduate Medical school, numerous honours and distinguished lectures, jt ed Clinical Aspects of Immunology

Rev Canon John Polkinghorne KBE FRS, Professor of Mathematical Physics, Dean and Chaplain, Trinity Hall, President of Queens', innumerable honours, distinguished lectures, prolofic author, Human Genetics Commission, Expert Group on Cloning, priest Anglican Church

Dr Chris Print, Fellow, Department of Obstetrics and Gynaecology, medically qualified

Rev Professor Michael Reiss, Bye Fellow, Chair, Institute of Education, London, zoologist from Trinity, bioethicist, author of leading textbooks in bioethics and reproduction, priest Anglican Church

Rev Canon Timothy Russ, Fellow Commoner, economics at Queens', priest Roman Catholic Church, source of Huddleston family protraits from Sawston Hall

Professor Stephen Smith, Professor of Obstetrics and Gynaecology, research in reproductive biology, molecular biology, collaborations with Bourne Hall, 'spin-off' biotechnology company

Professor Azim Surani FRS, Wellcome Trust/MRC Cambridge Institute for Medical Research, developmental biologist, research on imprinting mechanisms in the embryo

Dr John Tudor, Emeritus Fellow, former Director of Studies in Medicine, Department of Radiology, School of Clinical Studies, Addenbrooke's Hospital