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Preimplantation Genetic Diagnosis and 'slippery slopes'

13 May 2007
By Dr David King
Director, Human Genetics Alert
Appeared in BioNews 407
Recent news stories about the development of PGD tests for familial Alzheimer's disease and congenital fibrosis of the extraocular muscles (CFEM) have raised questions about 'slippery slopes' and the limits of PGD.

Although not a disabled people's organisation, Human Genetics Alert approaches these issues from a disability rights perspective.  I am disabled; my condition, though acquired, may be partly genetic. Disability rights organisations define disability according to the Social Model of Disability, which views disability as primarily caused not by people's physical impairments, but by discrimination and other social factors, such as lack of accessibility, inadequate support, etc. They contrast this with what they view as a reductionist and often oppressive Medical Model, which fails to see the person, but focuses on the impairment and aims to normalise physical difference, through aggressive and sometimes unwanted medical interventions (eg. cochlear implants), or by preventing the birth of disabled people. Because able-bodied people, especially doctors, focus on the impairment, they systematically underestimate people's ability to cope with impairments and live a joyful, worthwhile life. I would argue that if disabled people's perspectives are taken seriously, we would view far fewer genetic impairments as really being inconsistent with a worthwhile life, and therefore offer prenatal screening and PGD for a far narrower range of conditions than currently.

The problem with PGD is that in the logic of the situation it creates, there is no inbuilt brake on what is selected against. Unlike prenatal testing, where there is an established pregnancy, a fetus to which there is an emotional attachment, and the choice is between something or nothing, in PGD we must choose between multiple embryos. Since no one is apparently harmed by the selection, what can be the objection to selection against minor impairments or even 'positive' selection for cosmetic features etc?

In a large population, there will always be some parent, who, naturally wishing to prevent their future children suffering, is prepared to take the next step along the continuum of severity of impairment, and each step logically justifies the next.

But the apparent lack of harm is an illusion. I leave aside here the question of whether we can call the existing practices eugenic.  In my view we can, and understanding the persistence and continuity of eugenics throughout the last hundred years makes a big difference to the way we think about these issues.  But for present purposes it does not matter what we call it: the point is that real harm is being done.

From a perspective that is based in the real lived experience of disabled people, the contribution that they make to their families and to society and the equal value of their lives does not require detailed exposition. Allowing our removal harms society.

It is also obvious that giving official sanction to allowing them to be selected against does harm to society at large and gives a very hurtful message to disabled people who are actually alive. Philosophers may prove to their heart's content that allowing a negative selection is completely consistent with combating discrimination against and increasing support for living disabled people. Disabled people who live in the real world know better.  Everyone knows how society's negative attitudes towards disabled people put direct pressure on parents, especially disabled parents, to avoid having disabled children. Would we expect a black immigrant, living in a hypothetical country with racist immigration laws, to believe us when we say that, despite the continued existence of these laws, every one is really delighted that they are here? These messages are hurtful to disabled people and are inconsistent with the values of our society that professes to value diversity and abhor discrimination. Colin Gavaghan recognises the truth of this in his recent BioNews Commentary (1), but argues that we should therefore remove all restrictions on selection, a perverse conclusion that can only be explained by a severe dose of neoliberal ideological bias.  It is clear that the less severe the conditions selected against, the stronger is the message that disabled people in general are an annoying burden and it will be much better if they were not around, and the narrower becomes the socially acceptable range of physical differences.

So, we have two opposing very significant values, of avoiding suffering to individuals and avoiding harm to society: we must strike a balance and this inevitably means 'drawing lines', although there should always be some room for the views and circumstances of different families to be taken into account.

I am sometimes told that I am hard-hearted in trying to draw lines. Those who make such accusations should consider their own sensitivity to the suffering of disabled people in a society which seems happy to prevent their coming into existence. I am not opposed to using PGD for the most severe conditions, whether suffering is great and the condition invariably fatal and untreatable. But late onset disorders, especially where the odds of ever developing the condition may be close to 50/50 and preventive and curative treatments exist and/or are likely to be developed in the future, are at least one step too far.

In the debate on genetics, disabled people often complain that genetic research provides tools to prevent disabled people being born, but offers them nothing by way of treatment. Geneticists respond that their aim is not to eliminate disabled people, and that they are confident that research will provide cures, although they acknowledge that this will take time. Very well, let us take them at their word. According to this argument PGD may legitimately be offered for severe early-onset conditions, but for conditions which will not be manifest for several decades, we should certainly not offer PGD, since we must expect treatments to be developed in that time. To offer PGD in such cases would appear to vindicate disabled people's suspicion that these technologies are being developed in order to prevent disabled people being born.

In my view the phrase 'serious medical condition', which the Human Fertilisation and Embryology Authority (HFEA) uses as its main criterion has been stretched beyond breaking point in the case of CFEM, where pain is not a major issue, the impairment has no impact on life expectancy and treatments exist. The trouble is that the word 'serious' is not unambiguously defined in medical discourse and has everyday meanings which interfere. An example is genetic predisposition to breast cancer, which is, in everyday parlance a serious disease, yet it is late onset, the penetrance is still unclear and treatments exist. The word 'serious' is used to offer the public reassurance that PGD is not being used to prevent minor conditions, but in fact it does not offer the necessary protection.

If we want to take seriously the harmful social consequences of selection against more minor impairments, and since we cannot realistically expect parents to put these before the suffering, however minor of their own children, society has to exert its influence, through state regulation. Doctors cannot be trusted to self regulate, not only because they often have financial incentives to take patients, but because their primary focus is always on preventing suffering and, of course, they are steeped in the Medical Model.

There is inadequate space here to spell out what all the elements of an adequate regulatory guidance would look like. I am not talking about a rigid list of conditions, but rather a set of criteria. There must be flexibility to deal with individual family circumstances, but the voice of disabled people and of society at large needs to be heard much more strongly. Most crucially, we need to create a society in which disabled people are welcomed, supported and treated as equals. When we have achieved that, we can look again at the criteria for offering PGD, but until then we should err on the side of restriction.

1) Embryo testing: Why drawing lines risks devaluing the disabled C Gavaghan, BioNews March 13 2007
20 June 2011 - by Stevienna de Saille 
Arising from Dr Antoinette Rouvroy's doctoral research, Human Genes and Neoliberal Governance was originally published as a hardback in 2008, but has only recently become available in a paperback edition affordable to the general reader. In between those two dates much has happened in the field of genetics and governance, both globally and in the UK...
7 July 2008 - by Ailsa Stevens 
BioNews reporting from ESHRE conference, Barcelona:By Ailsa Taylor: Amidst current debate about the implications of allowing couples to select embryos free from conditions with later onset, incomplete penetrance and (limited) treatment options, ethicists have recommended that parents undergoing pre-implantation genetic diagnosis (PGD) should, in certain circumstances, be allowed to...
11 June 2007 - by Dr John Gillott 
The UK Draft Human Tissue and Embryos Bill, published recently, explicitly covers a number of uses of preimplantation genetic diagnosis (PGD). In this commentary I concentrate on just one - PGD to avoid diseases or disorders with a genetic component. The Draft Bill proposes that a licence can only be granted...
13 May 2007 - by Danielle Hamm 
The UK's London Bridge fertility clinic has performed pre-implantation genetic diagnosis (PGD) to ensure a couple have a child free from congenital fibrosis of the extraocular muscles (CFEM), a hereditary eye movement disorder. PGD involves taking a single cell from a 2-4 day old embryo and...
13 May 2007 - by Danielle Hamm 
The UK's London Bridge fertility clinic has performed pre-implantation genetic diagnosis (PGD) to ensure a couple have a child free from congenital fibrosis of the extraocular muscles (CFEM), a hereditary eye movement disorder. PGD involves taking a single cell from a 2-4 day old embryo and...
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