pp. 249-252 in
Bioethics in Asia
Editors: Norio Fujiki and Darryl R. J. Macer, Ph.D.
Eubios Ethics Institute
Copyright 2000, Eubios Ethics Institute
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7.3. Moral Controversies on Preimplantation Genetic Testing
Manchester University, UK.
Recent studies have indicated that handicaps due to genetic disorders or congenital malformations is one of the major pediatric health problems. More than a quarter of all deaths in the first year of life were due to fetal abnormalities (1), which has alarmed scientists and parents into seeking a esolutionf for this condition. Fear of severe genetic disease in their children can make parents do extreme things, including even infanticide. Until a couple of decades ago, these disorders were detectable only after birth, because there were no means of evaluating embryos or fetuses accurately. However in recent years, the introduction of various prenatal testing (PNT) techniques and advances in understanding human genetic diseases and their diagnosis have offered some options in order to prevent the birth of afflicted children.
Although PNT techniques were initially described in the nineteenth century, it was not until the middle of this century that the technique was applied to prenatal diagnosis (PND) and the management of various genetic disorders and congenital malformations. Today, prenatal screening and diagnostic techniques are widely used. It has been suggested that, approximately 90 per cent of present women in the UK make use of some form of PND (2).
As I have argued elsewhere, PND may have four main purposes;
1) to inform and prepare parents for the birth of an affected infant;
2) to allow in utero treatment, or delivery at a specialist centre for immediate postnatal treatment;
3) to allow termination of an affected fetus;
4) to provide information so that parents may choose between 1-3 (3).
As it appears, the goal of PND is to help couples make an informed choice, one which they feel is best for themselves and their families. After many years of discussion, professional standards and laws have influenced the clinical application of PND and have helped to solve many of the complex ethical issues. Yet problems still arise. In practice it has been observed that PND is generally being used to diagnose abnormality and then terminate the life of the prenate (4). There is a little doubt that relatively non-invasive technology whose primary purpose is to diagnosis treatable disorder and cure them before or after birth would be warmly welcomed by parents and ethicist alike. However, the present reality is that prenatal diagnosis rarely leads to fetal therapy. In fact, far more normal fetuses are killed as a result of a Chorionic Villus Sampling (CVS), a widely used PND procedure (5). Beside these, prenatal diagnosis of some diseases, like Huntingtonfs chorea, warn the parents that one of them is due to develop this fetal disease. Without being appropriately counseled beforehand, facts such as these raise complex problems for the couple, as they discover the nature of their own genetic difficulties. It is possible to specify some other negative consequences of PND, but my main objective in this article is to concentrate on a particular PND technique, that is, preimplantation genetic testing (PIGT) (6).
Now it is becoming possible to diagnose genetic disease in prenates before they implant -so allowing the preimplantation diagnosis of inherited disease. The first deliberate attempt to introduce the preimplantation diagnosis (PID) of genetic disease was carried out in 1967 when an attempt was made to identify the sex chromatin body of an intact rabbit blastocysts by examining under fluorescence microscopy (7). Some attempts were made to use PIGT in human embryo during e80s. Although there are some concerns about the accuracy of the techniques, PIGT of human genetic disease is being conducted in various centres throughout the world in the e90s.
The majority of couples who are at risk of giving birth to a child affected by an inherited disorder discover this only when an affected child is born. The availability of PIGT has allowed healthy children to be born to couples who would have refrained from reproduction otherwise. In general, PIGT aims to avoid the possibility of an affected pregnancy completely. It is based on the simple strategy of sampling genetic material from eggs or embryos within the first week of their development following fertilization. This material is used to detect whether the genetic defect is present and whether the embryo will be affected by the disease. This procedure would make possible the selection only of healthy embryos for implantation, or the genetic modification of embryos with disability or genetic damage prior to implantation.
It is possible to look at PID in three different stages. First, is the preconception diagnosis of the first polar body, the non-invasive diagnosis of embryos, or the excision of one or more cells from them for typing. Second, is cleave biopsy that relies on invasive methods of excising one or more cells from cleaving embryos, or trophectoderm from blastocysts. And the third, is blastocyst biopsy, that use blastocysts gained by IVF or uterine lavage. All of these procedures have advantages and disadvantages of their own (8).
At first sight, PID seems an ideal form of PND. It is argued that PID is less problematic from a moral standpoint since it involves discarding an early embryo rather than the termination of a fully-fledged pregnancy (9). Beside this, women would have easier relief using PIGT as opposed to PND to screen for genetic disease. It is known that diagnosis of an abnormality on PND leads to loss of confidence about the pregnancy, negative attitudes towards the baby and maternal anxiety. Couples who are at high risk for genetic disease, yet would be unwilling to abort an affected fetus, have a new door open to them with PID.
Beside other disadvantages, it is said that some of the PND techniques are highly invasive and physically traumatic with significant numbers of complications, including loss of healthy fetuses, fetal injuries, maternal bleeding and miscarriages do occur during the application of these techniques (10). However PIGT is more abstract and less invasive than other PND technologies. PIGT occurs at an earlier time than other PNDs, up to five days versus ten-sixteen weeks respectively which may lessen feelings of emotional attachment. It is argued that, the earlier the diagnosis of genetic conditions the easier the moral choices for many women or couples. For those who hold that the early fetus (i.e. epre-sentiencef or not yet a epersonf) is morally different from the older fetus, early identification of fetal genetic conditions will diminish the moral confusion of abortion (11). Edwards, the pioneer of in vitro embryology, has noted that; gIdentifying embryos with genetic abnormalities would offer an alternative to amniocentesis during the second trimester of pregnancy, and the eabortion in vitrof, of a defective preimplantation embryo.....would be infinitely preferable to eabortion in vivof at twenty weeks of pregnancy or thereabouts as the result of amniocentesis are obtainedh (12).
Although it seems ethically less problematic, there are still objections to the manipulation on human preimplantation embryos. These objections are generally based on the view that there is, in principle, no difference between an eight-cell embryo, and a fetus or a child. They are all human individuals and, since informed consent is not possible, should not be interfered with. On this basis, terminating an affected pregnancy halfway through the pregnancy is no more or less acceptable than discarding affected preimplantation embryos. The opposing view draws a sharp distinction between these stages of a human being's development and consequently argues that the ethical constraints are different at each stage. In this case, manipulation of early embryos to remove cells for genetic analysis is acceptable and some would argue that discarding affected embryos is preferable to doing so at a later stage.
It was argued that, since pre-embryonic chromosomal anomalies are a major cause of IVF failure, if only chromosomally normal pre-embryos (or at least pre-embryos normal for specific chromosomes) were to be transferred, there might be a significant increase in the success of IVF (13). However when the loss of embryos during the procedure, especially in polar body biopsy and cleavage biopsy technique is concerned, it is not necessarily going to increase the overall success (14).
A concern leveled at PIGT is that it may lead to eugenics. During this procedure the prenates which have less than perfect genetic constitution would be eliminated. Meith argued that, gAfter prenatal diagnosis, at least theoretically, there is a possibility that a couple will decide to carry a genetically abnormal fetus to full-term. In the context of preimplantation diagnosis and IVF, the decision making process is eliminated; the genetically abnormal embryo will not be implantedh (15). This is an ongoing discussion, whether we should prevent bringing a life into the world with esufferingf, and whether preventing bringing a disabled child into the world is a eeugenicsf. Harris argues that, we have an obligation to prevent suffering and disability, or, more abstractly that we should try to produce a world with less rather than more suffering in it, that we should try to produce a happier world (16). Of course this is what morality requires. And he further argues that, gThere is clearly a moral obligation to provide such screening where possible so that parents can have the opportunity to choose not to bring suffering or disability into the worldh (17).
However there is another problem, what constitutes an abnormality or disability? and should we eliminate fetuses on the basis of disability? As I have argued in another occasion (18), disability, handicap, abnormality and malformation are relative concepts. However, everyone can possibly agree that these are the conditions nobody would like to be in. Therefore, how can it be considered as eugenics to prevent someone being in one of these conditions? But this does not necessarily mean that it can be justified to terminate the life of an individual to save him suffering from disability. We can choose between being born with health and being born without it, but we cannot choose between a worldly existence or none at all, since the difference between existence and non-existence is beyond comparison (19).
Another concern about the, so called misuse of PIGT is sex selection. The usage of PND techniques only for sex determination followed by termination of pregnancy on a finding of eundesired sexf fetus has already been declared as an atrocious and unethical in various occasions (20). And this can be applied to PID as well. However, there are some medical situations where it would clearly be of benefit for a child to be preselected in terms of sex. For instance with genetic disorders and illness which are sex-connected, such as hemophilia and Duchenne muscular dystrophy, where normally only males are victims, although females may be carriers. Beside this it would be easy to understand a parental wish to have a girl or a boy in terms of simply satisfying the desires or needs of the future father and/or mother or of others in the family. As Mahoney argued, gParents determine their childrenfs genetic constitution, its environment, its character and its entire future by the unavoidable choices they make. And it is hard to see why, within such a chain of choices, the choice of sex should be singled out for particular moral disapprovalh (21).
As a matter of fact, there seems little moral difference between the will to have a healthy child or the will to have a girl or boy. Next to being healthy or handicapped, being male or female is morally neutral. Therefore preference in one of these does not necessarily mean having a negative attitude upon the other. In an ideal world, sex preference of the parents should be taken in the same account to the preference to have a healthy child. If one has a right to do something to have (or prevent the birth of) a disabled child, he also should have the same right to have (or prevent the birth of) a child of a particular sex. Therefore it is equally right (or wrong) not to implant a male/female zygote into the womb as not to implant a genetically abnormal embryo.
So it appears PIGT is not free from controversy, criticism against it is similar to that made against other PNDs. However it would be a short-sighted to reject it under the influence of the potential negative aspects while ignoring the actual advantages for the individual couples. Whether we are against it or not, termination of pregnancy subsequent to PND is a reality. Although it is very discomforting, couples do prefer termination when they discover their childfs abnormality (or even its gender). It is already too late to discuss the moral acceptability of abortion, since it has been so widely accepted and practiced in all regions of the world, developed and developing (22). The main objection to abortion comes from the uncertainty of the moral status of the prenate, and the wrongness of terminating a life which has already begun.
Therefore, prior to discussing the ethics of PND and PIGT in particular we must resolve the problem of the moral status of the prenate. I have argued elsewhere that this is an extremely complicated and controversial issue which has not yet been resolved (23). However it is clear that everyone, except those who believe human life begins with conception and that life must be protected from then (24), agrees that to terminate the life of an eight-cell zygote is morally less problematic than to terminate the life of a ten-week or four-month fetus. Therefore, since we cannot prevent people terminating the pregnancies if the PND result is unfavourable, we should first determine the emorally safef period to manipulate prenates, and secondly prefer PND techniques which enable us to operate within this period. It seems that PIGT suits this definition. With PIGT, it is possible to inform parents about the genetic construction of their future child and let them make the most suitable decision for themselves and their future.
1. Atkins, AFJ and Hey, EN. eThe Northern Regional Fetal Abnormality Surveyf, in (eds.) Drife, JO and Donnai, D. Antenatal Diagnosis of Fetal Abnormalities, Springer-Verlag Ltd., London, 1991, pp. 13-34.
2. Whittle, MJ. eRoutine Fetal Anomaly Screeningf in ibid. pp. 35-43.
3. Aksoy, S. ePrenatal Testing: An Ethical Perspectivef, The New Journal of Medicine, 13:2 (1996),
4. ePrenatef is used throughout the article as a general term cover all prenatal stages of development rather than misusing the medically defined terms of ezygotef (the first week after fertilisation), eembryof (the start of the third week until the end of the eight week after fertilisation) and efetusf (nine weeks after fertilisation until birth), which are intended to refer to specific stages of development before birth.
5. Boss, JA. eFirst Trimester Prenatal Diagnosis: Earlier is not Necessarily Betterf, Journal of Medical Ethics, 20 (1994), pp. 146-51.
6. In this article I will use preimplantation genetic testing (PIGT) and preimplantation diagnosis (PID) interchangeably, that both means roughly the same procedure.
7. Edwards, RG. and Schulman, JD. eHistory of and Opportunities for Preimplantation Diagnosisf in (ed.) Edwards, RG. Preconception and Preimplantation Diagnosis, Cambridge University Press, Cambridge, 1993, pp. 3-42.
8. Penketh, R. eThe Scope of Preimplantation Diagnosisf in ibid. pp. 81-97.
9. Stuben, J. eSmokescreen of Preimplantation Diagnosisf, Biomedical Ethics, Vol. 1:2 (1996), pp. 7-8.
10. MacLahlan, NA. eAmniocentesisf in (eds.) Brock, DJH., Rodeck, CJH. and Ferguson-Smith, MA. Prenatal Diagnosis and Screening, Churchil Livingstone, Edinburgh, 1992, pp. 13-24; Sutton, A. Prenatal Diagnosis: Confronting the Ethical Issues, The Linacre Centre, London, 1990, p. 29.
11. Gert, B., Berger, EM., Cahill, GF., Clouser, KD., Culver, CM., Moeschler, JB. and Singer, GHS. Morality and the New Genetics, Jones and Bartlett Publishers, Sudbury (Massachusetts), 1996, p. 202..
12. Edward, RG. and Purdy, J. (eds.) Human Conception in Vitro, Academic Press, London, 1981, p. 373.
13. de Wert, G. eThe Ethics of Preimplantation Genetic Diagnosis: A Gordion Knotf, Biomedical Ethics, 1:1 (1996), pp. 9-10.
14. Penketh, op. cit. p. 88.
15. Meith, D. eIn Vitro Fertilization: From Medical Reproduction to Genetic Diagnosisf, Biomedical Ethics, 1:1(1996), pp. 6-8.
16. Harris, J. eEthical Aspects of Prenatal Diagnosisf in (eds.) Drife and Donnai, op. cit. pp. 279-96.
17. ibid. p. 285.
18. Aksoy, S. eWhat is Disability?f, The Fountain, 3:10 (1995), pp. 28-9.
19. Aksoy, S. eTo Value Life and Existencef Eubios Journal of Asian and International Bioethics, 7:4 (1997), pp. 102-4.
20. Kusum. eThe Use of Prenatal Diagnostic Techniques for Sex Selection: The Indian Scenef, Bioethics, 7:2/3 (1993), pp. 149-65.
21. Mahoney, J. eThe Ethics of Sex Selectionf, in (ed.) Byrne, P. Medicine, Medical Ethics and the Value of Life, John Wiley & Sons, Chichester, 1990, pp. 141-57.
22. Aksoy, S. eAbortion: The Destruction of Lifef, EJAIB 7 (1997), 52-4.
23. Aksoy, S. ePersonhood: A Matter of Moral Decisionsf, EJAIB 7 (1997), 3-4.
24. Mahoney, J. Bioethics and Belief, Sheed & Ward, London, 1984, pp. 67-9.
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