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The Use of Embryos

Elizabeth Hemsley considers ethical arguments for and against a new embryo modification procedure.

A recent decision by the UK government to amend its Human Fertilisation and Embryology Act (HFEA) to allow for a procedure called mitochondrial donation was preceded by vigorous debate, as is usual in bioethical issues. The procedure was lauded by some as a triumph for scientific progress, while for others, it has raised the spectre of genetic engineering and so-called ‘designer babies’.

The case in favour of the procedure is easily expressed. Mitochondria, which exist in almost all cells in the body, are the biological mechanisms in cells responsible for converting food into energy. If mitochondria are defective, they are unable to provide sufficient energy for cells to function. The impacts of this are different depending on which cells are affected, but they can include blindness, deafness, heart, liver, or kidney disease, and other severe forms of impairment. Defective mitochondria are passed from mothers to their children, and a woman who has defective mitochondria cannot guarantee that her children will be free from these diseases and their potentially devastating effects. Mitochondrial donation is a procedure carried out on eggs or early embryos with defective mitochondria, to give her genetic offspring healthy mitochondria taken from a donor embryo. Afterwards, the embryo is implanted back into the womb, where it can develop into a baby free from debilitating mitochondrial disease. It seems a truism that preventing a child from being born with a potentially life-threatening condition is a good, indeed morally necessary, thing, so the case in favour of mitochondrial donation is easily understood.

8-cell embryo, 3 days after fertilisation
© Database Center For Life Science 2013

The case against has proven trickier to elucidate. Far from denying that preventing a child from suffering is morally required, opponents of mitochondrial donation are engaged in a complex unpicking of competing moral claims. Their position involves subtle claims about means and ends and moral status. In today’s culture, where deep philosophical soul-searching so frequently loses out to populism and rhetoric, there seems to be little media space to fully express these concerns. This has meant that the challenge to explain why mitochondrial donation seems unethical to some has not been well met. The philosophical concerns that lie at the heart of objections to it have remained ill-defined and obscure. In this article, I want to examine the prominent arguments that have been advanced in opposition to mitochondrial donation, and the refutations of them provided by its proponents. In doing so, I’ll also explain why none of these arguments really get to the heart of what is uniquely troubling about the procedure.

What Mitochondrial Donation Involves

As I said, the purpose of mitochondrial donation is to replace the defective mitochondria of a mother with the healthy mitochondria of a donor. There are two methods for achieving this. The first is pronuclear transfer (or ‘embryo repair’, to give it its media-friendlier designation). In this method, two eggs – one from a prospective mother who knows she is at risk of passing on defective mitochondria, and one from a donor with healthy mitochondria – are separately fertilised, creating two embryos. The mother’s egg is fertilised with the sperm of the intended father, as in IVF; the donor’s egg can be fertilised with donor sperm. The result is one fertilised egg with the genetic inheritance of both prospective parents, including the mother’s defective mitochondria, and one fertilised egg with the genetic inheritance of two donors, including healthy mitochondria. The aim of the procedure is to produce an embryo which has the genetic inheritance of the prospective parents and has healthy mitochondria. So a switch has to take place. This switch is actually performed by removing the nucleus of the donor egg – a cell’s nucleus is where all of the genetic information determining things like eye and hair colour, innate intelligence and athletic prowess is held. The nucleus from the prospective parent’s embryo, containing the genetic information to be inherited from them, is then placed inside the donor fertilised egg. If successful, the outcome is an embryo with the genetic inheritance of the prospective parents, but the mitochondria of the donor mother. The alternative method, maternal spindle transfer (or ‘egg repair’), follows this approach, but instead of fertilising the eggs before switching the nuclei, it first replaces the nucleus of a donor egg with the nucleus of the prospective mother’s egg, and then the resulting egg – which now has healthy mitochondria plus genetic information inherited from the prospective mother – is fertilised with the sperm of the prospective father.

Two Common Objections

Opponents to mitochondrial donation, including voices in the Church of England and the Catholic Church, typically expressed their concerns about it via two routes. One questions the ethics of using and destroying embryos; the other challenges the safety of mitochondrial donation, and worries about the unknown ill-effects which could be borne by the recipients, who were never able to give their consent to it.

Objection 1: The Moral Status of Embryos

The belief by some that the destruction of embryos is always ethically impermissible because life begins at conception provides them grounds for having strong objections to the first, embryo replacement, method. This is because the removal and destruction of the donor embryo’s nucleus to accommodate the nucleus of the prospective parents’ embryo, effectively amounts to destruction of the donor embryo. The nucleus contains all of the genetic material which makes us who we are, and unique. Once this is destroyed, the donor embryo is essentially just an empty vessel. Transplanting the nucleus from the prospective parent’s embryo into this vessel effectively transforms it into another embryo. It now carries all of the unique genetic material of the parents’ original embryo, albeit that it is using the healthy mitochondria of the donor. The blueprint of the unborn person that was contained within the nucleus of the donor embryo no longer exists. For those who see even recently fertilised eggs as human lives, this is sufficient to make the procedure ethically impermissible.

However, this complaint fails as a targeted objection to mitochondrial donation per se, because it ignores the fact that in the UK and elsewhere, early embryos are already legally experimented with and destroyed in labs conducting stem-cell research. In this respect, mitochondrial donation does not entail anything that’s not already happening. As a society, we are a long way past the point of holding embryos as sacred entities with a moral status anywhere near equivalent to that of living, breathing people. Insistence upon the absolute moral status of embryos ignores the reality of how they are already viewed and treated. A more socially realistic argument would couch the moral status of embryos relative to grown human beings. The view that it is okay to use embryos for scientific purposes, if this will help to minimise human suffering, can then be accommodated on the basis that the lives of grown people are generally held to be more valuable than those of embryos. By this reasoning, stem cell research is off the hook, and proponents of mitochondrial donation can now argue that by the same logic, it too is off the hook. At the cost of one fertilised egg, they claim, mitochondrial donation can prevent a human being from suffering, and possibly from dying a premature death. It is therefore permissible under the same justification as stem-cell research.

However, as I will argue, the attempt to weigh the moral value of a destroyed embryo against the moral value of an adult human life is disingenuous when the adult human life in question would not exist independently of the destroyed embryo. This is not the main ethical issue in this situation. So for those who are not committed to a view of embryos as morally sacrosanct, but who nevertheless want to say that there is something worrying about mitochondrial donation, the idea that fertilised eggs are morally inviolable provides only a straw-man argument, and unanswered concerns remain.

Objection 2: Unknown Risks

The second common objection to mitochondrial donation is that we cannot be sure of its safety, and that unborn children, unable to give their consent, will be its guinea-pigs, with unknown risks.

This objection expresses a concern about what the physical impacts of this procedure might be on the children it creates. It is a valid concern, but one which relates to the stage of scientific development the procedure is currently at, rather than to anything essential about the procedure in itself. These concerns about the unknowns of mitochondrial donation will be addressed in time, and do not have much to say about the legitimacy of the procedure per se. All new medical and scientific discoveries take us into uncharted territory. For those who accept that safety concerns are inevitable in any new and progressive procedure, this argument fails to capture anything fundamentally and uniquely troubling about mitochondrial donation.

A More Convincing Concern

Notwithstanding the two common objections outlined above, there remains something unsettling about the legalisation of mitochondrial donation that nags to be addressed. Basically, the third objection is that legalising this procedure places us on the slippery slope of a type of consumerist mentality, at the bottom of which is the chilling notion of babies designed by their parents to exhibit certain ‘favourable’ genetic traits, and discarded when they fail to do so.

This objection comes closest to explaining the intuitive disquiet that many feel when confronted with the prospect of genetic manipulation. It is a disquiet that is difficult to pin down, but it has its foundations in the notion that we should not seek to choose what type of people are allowed to exist.

Harvard ethicist Michael Sandel attempts to explain this in his book The Case Against Perfection (2007). He argues firstly that one virtue of parenthood lies in the fact that “more than any other human relationships” it teaches and urges an “openness to the unbidden.” For Sandel, the decision by parents to genetically alter their unborn child alters this dynamic, and so restricts the opportunity for the unconditional accepting love that normally exists from a parent towards a child. Sandel also points to the argument of German philosopher Jürgen Habermas, that in order to think of ourselves as free, we must understand ourselves as originating through a natural process, or at least through a process that’s not controlled or dictated by another person. For Habermas, a child who is designed by their parents would not truly be free, because they owe essential features of themselves to the deliberate choices of another.

Defenders of mitochondrial donation dismiss concerns related to genetic engineering, such as the slippery slope argument, as misplaced. They point out that the prospective parent’s potential child undergoes no significant change as a result of the procedure, save for benefitting from the provision of healthy mitochondria. The mitochondria this embryo inherits accounts for less than 0.1% of the genetic material that makes up a person. Replacing the defective mitochondria of an embryo has no influence over crucial genetic traits such as eye colour, hair colour, height, or innate intelligence. As such, its proponents argue that the procedure is not genetic engineering in the sense that producing a ‘designer baby’ would be. Its effects, they argue, are purely and straightforwardly medical. An embryo which was unhealthy is now healthy, and all other things remain equal.

However, even if we accept this interpretation of the process as not being genetic engineering (and I don’t accept it), it does not dispel fears that mitochondrial donation could mark the opening of a floodgate through which the tide of genetic engineering inevitably crashes. This is the ‘slippery slope’ worry: that the acceptance of mitochondrial donation will also make (other forms of) genetic engineering more likely. For instance, before the new legislation, it was prohibited in the UK to use in fertility treatment any sperm, egg or embryo that had been genetically altered in any way, either through changes to its nuclear DNA (contained in the nucleus), or through changes to its mitochondrial DNA (in the mitochondria). The HFEA is now amended to allow for the alteration of eggs and embryos only for the updating of mitochondrial DNA. Proponents point out that this change in legislation in no way permits changes to the essential attributes of unborn children. For that type of change to be permitted, further legislation allowing for changes to the nuclear DNA of sperm, eggs, or embryos would need to be passed. So genetic engineering of the kind objected to by Sandel and Habermas is no closer to being legal as a result of the amendments allowing mitochondrial donation, at least in the UK.

But there is something more to the worry about the genetic slippery slope than a straightforward concern about what practices an amendment to the law might permit. There are also concerns that once we justify the removal of initial conceptual boundaries, for instance between a genetically altered and a genetically unaltered embryo, there will be little to prevent us from continuing down that path: if we can justify erasing the distinction between an altered and an unaltered embryo, why not also the distinction between altering mitochondrial DNA and altering nuclear DNA? This worry attempts to grasp at something of ethical significance about the precedent the legalisation of mitochondrial donation sets. For the remainder of this article, I will try to set out what I take that to be.

A Worrying Precedent

As a procedure, mitochondrial donation creates a uniquely problematic scenario not previously encountered, and not yet adequately addressed from an ethical standpoint. ‘Embryo repair’ mitochondrial donation creates two embryos, one of which exists purely as a means of ensuring the healthy development of the other. Regardless of what we judge the moral status of embryos to be (equal to grown humans, or less valuable), the two embryos created here must be judged as having the same moral status as each other. And yet one must be destroyed to facilitate the healthy development of the other.

To my knowledge, the challenge of how this trade-off between the two embryos can be ethically justified has not been adequately acknowledged or addressed anywhere in public debate. Instead, a higher moral status has simply been assumed for the embryo with defective mitochondria, and justifications for mitochondrial donation have focussed on the necessity of the procedure if this embryo is to develop into a healthy infant. As discussed, many have attempted to justify the destruction of the donor embryo by alluding to the medical necessity of doing so for preventing the suffering of the human being that the other embryo will (hopefully) become. However, how can the destruction of one embryo be justified by the need to guarantee the health of a person, since either embryo might have become a person? We are left wondering why the well-being of the person that one embryo has the potential to be is to be valued so much more highly (and indeed at the cost of) the person that the other embryo has the potential to be.

Someone might argue that the embryos possess a different moral status to one another in virtue of the value that the prospective parents place on their own embryo, as the one which will hopefully become their child. But while we can accept that the prospective parents might have an understandable reason for preferring the embryo which inherited its DNA from them, this does not naturally translate into a justification for the objective moral preference for that embryo. Each of us is likely to prefer our own family members to total strangers, for example; but this does not automatically afford our own loved ones greater moral status. So it remains to be demonstrated how the destruction of one embryo in favour of another can be ethically justified from an objective standpoint.

We are now getting closer to what is uniquely troubling about a decision to legalise mitochondrial donation. The justification for the legalisation of this procedure is that some parents would prefer to have genetic offspring rather than adopt or opt for surrogacy. Proponents of the medical necessity of mitochondrial donation recognise however that (as with stem cell research) a justification based on the prevention of human suffering carries greater moral urgency than one based on the satisfaction of human preferences. But as I outlined, that justification does not exist in any independent sense. Rather, we have the favouring of one potential person over another, and it is ultimately the preference of the prospective parents that provides the justification for assigning a higher moral status to one embryo over the other. Now we seem to be not only on the edge of a slippery slope, but rapidly hurtling down one. Mitochondrial donation requires the creation of an embryo which will only ever exist as a donor, but which has no moral status, and this is not necessitated by any morally urgent ends, such as research that could save the lives or prevent the suffering of hundreds of thousands of future humans. Rather, it serves the ends of ensuring the healthy development and flourishing of another, subjectively preferred embryo. What is so troubling about mitochondrial donation, then, is that it necessitates a scenario whereby we sanction the destruction of one like entity in favour of another based purely on our subjective preferences.

This sets a worrying new precedent about the types of choices and trade-offs that can be justified when assigning moral status to morally equivalent ‘pre-person’ entities, if these choices and trade-offs will satisfy the subjective wants of an existing society, or, as with mitochondrial donation, of a handful of its members. There seems to be something rather consumerist about the idea that an embryo (or even a human egg) can be utilised in such a way – that is, not to address the morally pressing ends of reducing acute human suffering, but to satisfy subjective wants. If our subjective desires can create the justification for the trade-off necessitated by mitochondrial donation, what other types of trade-off might our social preferences eventually justify? What about a scenario akin to that described by Kazuo Ishiguro in his dystopian novel Never Let Me Go (2010), where human embryos are cloned to grow adults specifically for organ donation? Just as the donor embryo in mitochondrial donation is never considered to have moral status equivalent to the embryo it will ‘save’, these clones are not considered to have moral status equivalent to the humans their harvested organs save. The difference is only that this clone scenario treats one grown human as merely a donor and another as a morally valuable entity, whereas mitochondrial donation treats one embryo as a merely a donor and another as a morally valuable entity. The real justification remains the same: that existing people will achieve a higher happiness quotient if the donor is created than if not. And having now created a precedent whereby moral status is not objective, but is determined by the wants and preferences of an existing society, we may come to find that preventing the creation of designer babies is the least of our worries.

Elizabeth is doing a PhD in Political Theory at the University of Hong Kong. She has an MA in Philosophy from the University of Edinburgh.

• An early expression of the ideas contained in this article appeared in Athena (imagineathena.com), and I am grateful to readers of the magazine for their comments.