Is mitochondrial replacement therapy eugenic and incompatible with human dignity?

A group of European parliamentarians from the Council of Europe, led by British Labour MP Jim Dobbins, recently issued a declaration objecting to the Human Fertilisation and Embryology Authority's policy advice on experimental mitochondrial replacement therapy (MRT). The declaration claims that MRT is eugenic and inconsistent with human dignity. These are substantial moral claims, ones that deserve closer scrutiny, and it is an interesting and important exercise to consider how successful such arguments are.

First, consider the argument that MRT is incompatible with human dignity according to Article 24 of the UNESCO Universal Declaration on the Human Genome and Human Rights.  MRT is a form of germ-line therapy and Article 24 indicates that such interventions 'could be contrary to human dignity'. However, the force of this claim depends very much on what is meant by 'human dignity', something not explained in Article 24.

Some explanation is offered earlier, in Article 2 of the same UNESCO Declaration, which says:

(a)    Everyone has a right to respect for their dignity and for their rights regardless of their genetic characteristics.

(b)    That dignity makes it imperative not to reduce individuals to their genetic characteristics and to respect their uniqueness and diversity.

In the light of this explanation, why might MRT be inconsistent with human dignity? One reason is that it alters a person's genetic makeup. But in cases where MRT would substantially benefit the person (by curing or preventing mitochondrial disease) what reason is there to prioritise the preservation of that person's original 'diseased' mitochondrial DNA (mtDNA) over his or her welfare? Such a prioritisation seems unfounded and furthermore is liable to fall foul of the very principle at stake here: human dignity. For, arguably at least, attaching more importance to the preservation of people's 'diseased' mtDNA than to the prospect of treatment and cure is itself an instance either of 'reducing individuals to their genetic characteristics', or of failing to respect their rights (such as a right to healthcare, or to be free from avoidable suffering) 'regardless of their genetic characteristics'.

Mitochondrial DNA disorders can cause terrible suffering and even death. One example is Leigh syndrome which results in the gradual loss of motor control in one's body and often results in death during childhood. It would be perverse if the UNESCO Declaration actually aimed to restrict beneficial therapies because they obstructed the passing on of mtDNA disorders to future persons. If this were true then the Declaration would entail subjecting individuals to avoidable suffering and/or premature death in order to preserve their inherited mitochondrial genes. It is difficult to imagine how this could be what its authors intended.

Allowing MRT would not 'reduce individuals to their genetic characteristics', but could be said to do quite the opposite. By removing the risk of mtDNA disorders with MRT, we can help ensure that the lives of future persons are not dominated by the suffering that would otherwise be caused by a small number of mutated mitochondrial genes. MRT has the potential  to allow future persons to focus instead on all of their other unique and diverse personal attributes, free from the constraints of an mtDNA disorder (1). It therefore appears that encouraging MRT is in the spirit of preserving and respecting human dignity according to the UNESCO Declaration, not the other way around.

Second, is MRT eugenic? Of course a lot hangs on what exactly is meant by 'eugenics'. If we use a narrow definition according to which eugenics involves some degree of state coercion, then provided that prospective parents validly consent, MRT will not be eugenic. If however a wider definition is adopted, according to which all interventions that improve population genetic health are eugenic, then perhaps MRT is eugenic (in this wide sense only). But then (again, only in this wide sense) so are many other widely accepted practices: for example, avoiding first cousin marriage, advising women to have their children before the age of 35 (to reduce the risk of fetal genetic abnormalities), and PGD (preimplantation genetic diagnosis) to 'select out' embryos with serious genetic disorders.

So if the objection to MRT is that it is 'eugenic' in the narrow sense then that objection is mistaken; MRT is not eugenic provided that it is consensual. But if, on the other hand, a wider sense of 'eugenics' is deployed then, while perhaps MRT is eugenic, it's not obvious that being 'eugenic' (in this wide sense) is necessarily wrong; nor is it obvious that MRT is any more 'eugenic' than many other widely accepted practices (2).

The European Parliamentarians also cite Article 3 of the Charter of Fundamental Rights of the European Union, which states that 'the prohibition of eugenic practices, in particular those aiming at the selection of persons, must be respected'. Yet it is not obviously the case that MRT involves the 'selection of persons'. Unlike PGD (which involves choosing between different embryos for implantation) and conventional egg donation (which allows women with known mtDNA disorders to use unaffected donor eggs instead of their own), MRT (or at least one form of it, pronuclear transfer, PNT) does not involve the selective use of embryos or gametes. Rather, it modifies and, if successful, prevents a determinate single embryo from having an mtDNA disorder. Hence, there may be good reason to see at least this form of MRT (PNT) as a case of gene therapy, rather than an instance of selective reproduction. This makes MRT, if anything, less vulnerable to charges of eugenics than the more conventional alternative, egg donation — and it is certainly no more vulnerable to such charges than is egg donation.

In summary, are the Euopean politicians' objections good ones? On closer inspection it appears that they are not. MRT does raise complex ethical issues which deserve attention. Who should be allowed to access these treatments if they do become available on an experimental basis? Is research into MRT the best use of scarce medical resources? Should mitochondrial donors remain anonymous? And are there ethical differences between the two main forms of MRT (pronuclear transfer and maternal spindle transfer)? We should focus our attention on these concrete issues and others like them, rather than dwelling on sometimes confused or confusing claims about human dignity and eugenics.