Choosing The Best Possible Child: The Ethics of Pre-Implantation Genetic Diagnosis

Pre-Implanatation Genetic Diagnosis is a technology with the great potential to reduce suffering but it also can be mis-used. What purposes should we use PGD for? Where should we draw the line?

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Imagine you have a recessively inherited genetic disorder such as Cystic Fibrosis, or sickle cell anaemia. You strongly desire to have your own biological children, but don’t want to risk them inheriting the disorder from you. You partner has testing to see if they are a carrier, but unfortunately, the test comes back positive— there is a 1 in 4 chance of your baby inheriting your genetic disorder if you conceive conventionally. You are left with a dilemma. You could:

(a)   Take your chances, conceive conventionally and hope that your child doesn’t inherit the disease.

(b) Conceive conventionally but have antenatal genetic testing such as amniocentesis or chorionic villus sampling (both involve obtaining a sample of the cells from the placenta or amniotic fluid and then carrying out genetic testing for abnormalities, both carry a risk of miscarriage of <1%) and then terminate the pregnancy if an abnormality is detected. 

(c)  Use screened donor sperm or eggs to conceive via IVF but your child will not be 100% biologically related to you and your partner. 

What would you do?

Fortunately for you there is another option – Pre-implantation genetic diagnosis also known as PGD and embryo selection. PGD involves producing embryos via IVF using your own eggs and sperm and then testing them for genetic disorders. It will allow you to screen your embryos for the genetic disorder before they are implanted and thus avoid being pregnant with an embryo that has the genetic disorder altogether.

Do this option change your decision? Would you choose this option? What are the ethical issues surrounding this technology? 

Welcome to the P-Value. I’m your host Dr Rachael Brown and this week we are continuing our dive into bioethics and discussing the ethics of a potent contemporary reproductive technology Pre-implantation genetic diagnosis for embryo selection. 

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Ethically the key challenges surrounding PGD relate to who should have access and for what purpose. It is a great example of how moving technology from the lab to social contexts can present significant ethical and public policy dilemmas. 

For many of those with severe genetic disorders within their families, the potential to stop the disease being passed on to future generations family members is an unquestionable good. For later onset degenerative diseases such as Huntington’s Disease and Spinal Muscular Atrophy, family members have watched love ones suffer and eventually pass away and justifiably want to end that grief and pain within their families.  With PGD we have the potential to make a huge difference to the numbers of people born each year which have the genes for developing all sorts of terrible diseases. Unsurprisingly, many of the communities with these diseases in these families have invested a great deal of time and effort lobbying the government to subsidised access to PGD and late last year a such coverage was provided by the Australian Government for a small set of diseases. In these cases, almost all agree that PGD is a good thing but there are lots of cases where the ethics surrounding the application of PGD is far less clear.

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A key challenge for PGD is that there is a great potential for it to be misused to select traits merely for aesthetic or cultural preferences. The dark 20th Century history of eugenics makes us unsurprisingly wary about anything in this area. There are however, many pushing for the use of PGD outside of medical contexts regardless. PGD for sex selection is one such case.

How often do you hear people talking about trying for a further baby to conceive a child of a particular sex? Wouldn’t PGD avoid the heartache associated with this? Currently Australian regulations allow sex selection of embryos only for medical reasons. For example, in cases where there is a higher likelihood of genetic disease being passed down through a particular sex. But sex selection for “family balancing” —the selection of one sex over the other for non-medical reasons—is allowed in other countries such as the USA and Australian couples do travel overseas to access the technology. If you do a cursory google search on family balancing in Australia, you will find several operators offering to organise overseas travel for PGD for family balancing purposes. Advocates of such testing being allowed in Australia for family balancing make the following comparison of options. Families, they say, have the choice to:

(a)  Take their chances, conceive conventionally and hope that their child is the gender they desire (roughly 50:50 chance), risking “gender disappointment” if they are not. 

(b) Conceive conventionally but have antenatal genetic testing such as amniocentesis or chorionic villus sampling (there newer forms of testing that are non-invasive that can detect sex with a high degree of accuracy from as early as 10 weeks of gestation) and then terminate the pregnancy if the “wrong” sex. 

(c)  Use reproductive technology (overseas) which allows you to screen your embryos for sex before they are implanted. i.e. avoid being pregnant with an embryo that has the “wrong” sex altogether.

Most, advocates say can’t afford option (c) and take option (b), undergoing early antenatal genetic testing aborting foetuses of the wrong gender. Skewed gender ratios in several countries, including China and India, suggest this practice is common. A 2018 analysis of data from the Australian Bureau of Statistics by researchers at Latrobe University showed that in at least some cultural communities in Australia gender ratios are also skewed implying that gender selection is occurring here too. Given that it seems like people are effectively undertaking gender selection already, why not then provide it for PGD in Australia?  

Aside from the many reasons we might have against sex selection in particular, one reason to reject PGD for these purposes is simply that it opens up the flood gates for selection on all sorts of other cultural and aesthetic traits.  If gender is ok, what about eye colour? Or height? Or intellectual capacity? Where would we draw the line?

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Legislation worldwide regarding the use of PGD typically restricts its acceptability (and legality) to cases of (serious) genetic abnormality. In Australia, for example, the NHMRC guidelines state that PGD may only be used to select against genetic conditions, diseases or abnormalities that would severely limit the quality of life of the person who would be born; select an embryo with compatible tissue for subsequent stem cell therapy intended for a parent, sibling or other relative; increase the likelihood of a live birth. 

Even if we accept this restriction, we cannot avoid ethical challenges. What for example counts as a genetic condition, disease or abnormality which would severely limit the quality of life of the person who would be born? What are the implications (ethical, social, otherwise) of allowing PGD for any particular disorder?

Looking at the list of diseases that have been taken to pass the NHMRC requirements the challenge of drawing this line becomes clear. Whilst some of the disorders that PGD can legally be used for are early childhood diseases like Gaucher Disease Type 2 which typically results in severe brain damage and death in early infancy not all the diseases are like this. There are many diseases on the list that still allow people to have what most people would describe as full and relatively long lives such as early onset Alzheimers, Marfan Syndrome, and Achondroplasia. 

Many ask whether we should be selecting against these diseases. Isn’t it discrimination? Doesn’t selecting against these diseases devalue those living with those diseases? 

One might worry, like bioethicist Julian Savulescu, that this sort of argument makes an unwarranted assumption that selection against implanting embryos carrying genes for a disease, implies a lack of value of people with the disease. To quote Suvalescu in a 2001 article, “It is important to distinguish between disability and persons with disability. Selection reduces the former but is silent on the value of the latter.” Do you agree? Does PGD imply a lack of value for people with a disease or disability? 

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Another concern of disability advocates relates to the sorts of judgements being made about whether something is or is not a severe enough disease for PGD. Specifically, they point out that because at least in part what counts as a disease or disability is a matter of the society in which a person is found, these judgements are arbitrary. 

Whether or not achondroplasia, or dwarfism, is a severe disease is also heavily context dependent. Many of the challenges faced by people with this genetic disorder are due to a lack of accommodations, rather than the disorder itself, yet you can do PGD for achrondroplasia. How do we decide which disorders are sufficiently “bad” to warrant PGD. How much should we ignore context? 

Furthermore, one might reasonably worry that the focus on PGD only serves to draw away valuable resources and attention from making society more equitable. 

What do you think? Most people would agree that there are clear cases here where PGD is warranted—some of the very nasty fatal early childhood disorders—but where we want to draw the line as a society on this technology is far from clear. 

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Pushing back on concerns about PGD, we can’t ignore individual reproductive autonomy. Despite recent developments in the US, there is a general agreement amongst those in liberal democracies that we shouldn’t force people to have children they don’t wish to have. It seems reasonable then to assume most would agree that forcing parents to have children with particular disorders is both cruel and violates their autonomy. If anything, so this line goes, PGD increases parental reproductive autonomy which is a good thing. 

Whilst persuasive, this line of reasoning does beg the question—where do we draw the line? Is it violating reproductive autonomy to not provide PGD as an option then for family balancing? 

Julian Suvalescu, offers a different argument for PGD in the form of a principle he calls “procreative beneficence” according to which couples (or single reproducers) should select the child, of the possible children they could have, who is expected to have the best life, or at least as good a life as the others, based on the relevant, available information. Suvalescu offers a simple example to motivate his principle. “A couple is having IVF in an attempt to have a child. It produces two embryos. A battery of tests for common diseases is performed. Embryo A has no abnormalities on the tests performed. Embryo B has no abnormalities on the tests performed except its genetic profile reveals it has a predisposition to developing asthma. Which embryo should be implanted?” Suvalescu says that since Embryo B has nothing to be said for it over A and something against it that it is only rational to implant A. Put simply he says, asthma is a state which reduces the well-being of people and thus is a morally relevant property on which we should base our decision. 

Returning to PGD, the principle of procreative beneficence suggests not only should PGD be available for improving well-being of those embryos that are implanted but that parents should employ it. Suvalescu indeed, goes as far as to say that in the future if the technology is more widely available and efficient that it may be that all parents should do it even for traits that are diseases. Indeed, it is for this reason that, Suvalescu’s principle doesn’t avoid the challenge of gender balancing —arguably, if parents are in a patriarchal society in which there is a strong preference for male over female children, they are selecting the child who is expected to have the best life of their possible children by choosing a male embryo. 

What do you think? 

Where should we draw the line on PGD? 

What about the moral responsibility of parents? Should they have PGD and embryo selection if they can? 

Where does parental reproductive autonomy fit in all this?