Three-parent embryos for mitochondrial disease? Twelve reasons for caution

The media is buzzing today with the news that Britain is planning to become the first country in the world to offer controversial ‘three-parent’ fertility treatments to families who want to avoid passing on mitochondrial diseases to their children (See BBC, Guardian, Times (£), Independent, Daily Mail and Telegraph).

The Department of Health announced yesterday that it would draw up draft guidelines to allow fertility clinics to offer the technique. The proposed guidelines would be released for public comment later this year, and Parliament would vote on a final version in 2014.

Scientists are currently researching two main three-parent IVF techniques. The first, being developed at Britain's Newcastle University and known as pronuclear transfer (PNT), swaps DNA between two fertilised human eggs. Another, called maternal spindle transfer (MST), swaps material between the mother's egg and a donor egg before fertilisation.

The BBC is heralding it as a ‘ground-breaking technique for preventing serious genetic disease’ and a ‘bold step for science and society’. Media reports are full today of reassurances that that mitochondrial DNA only accounts for 37 out of our 20,000 human genes and that this therefore is a small step that will be undertaken only under ‘strict safeguards’.

Most people accessing broadcast media will hear heart-rending accounts of affected families and will get the message that those opposing the move are Luddites and religious fundamentalists on the lunatic fringe.

But there are actually very good reasons we should not be going down this route. Here are just twelve for starters:

1. Even were this new technology to work (and there are huge questions about that) it would help only a very small handful of families and only a tiny fraction of those with mitochondrial disorders. One in 6,500 babies is born with mitochondrial disorder, about 200 per year in Britain. But only five to ten of these have conditions serious enough to merit this intervention.  The technology will not help the other 190 or the 12,000 people in the UK already living with mitochondrial disease.

2. Babies with serious mitochondrial disease will still be born as many families are not aware they are even carrying the abnormal genes until after the birth of at least one affected child. So this will largely be relevant only in preventing the birth of subsequent affected children to these families.

3. There are already alternative routes for these families to have unaffected children either through adoption or egg donation (although I personally have serious ethical misgivings about the latter).

4. Both techniques above involve cell nuclear replacement ‘cloning’ technology which has not yet been shown to work in humans. Whilst it appears to be effective in lower mammals like mice (see here) use of cloning techniques in higher mammals has resulted in huge numbers of miscarriages and the birth of large numbers of abnormal offspring. It took 273 attempts to produce Dolly the Sheep and she herself was abnormal dying early. There is a strong possibility that we may simply be trading mitochondrial disease for other abnormalities if babies are ever born after use of the technique.

5. It is likely that thousands of embryos will need to be produced and experimented upon in developing these techniques. Many, like me, who believe that human embryos are worthy of the utmost respect and protection as early individual human lives will argue that the end of producing an unaffected baby does not justify these means.

6. Tens of thousands of eggs will be required for this research. It is virtually certain that donated excess eggs from those undergoing fertility treatment will not be adequate to meet this demand and that egg harvesting from paid donors will be necessary leading to exploitation of  vulnerable women and exposure to  at times high-risk egg-harvesting procedures.

7. If successful, this research will cross an ethical and safety rubicon by allowing human germline genetic therapy for the first time in human history. The genes from the third parent will be passed on down the generations and will be impossible to remove from the family.

8. Any babies resulting from this therapy will have a third genetic parent whose details will not be on the birth certificate. This raises issues of personal and family identity for children born as a result of the technique and will inevitably lead to litigation involving parents wanting to assert maternity rights and children wanting information about all their genetic parents. Behind these cases will be the hugely emotive issues of custody and inheritance.

9. Allowing the technique will lead to further demands for extension in two ways. It will be argued that if we have accepted germ line therapy for mitochondrial disease then we should also accept it for genetic disorders transmitted by nuclear DNA and for less serious mitochondrial disorders. This will lead to pressure to extend the use of these techniques to other diseases. By backing germ line therapy even in these limited circumstances the UK is crossing a line that every other country which has considered the matter has concluded is too dangerous.

10. These techniques do not offer support or treatment to people affected with mitochondrial disease but rather are aimed at identifying these individuals at the embryo stage and genetically engineering them. There is more than an element of eugenic thinking here. Is it right for us to decide that lives with serious disability are not worth living to the extent that such people must be prevented being born or genetically altered to make them acceptable? This is a very dangerous slippery slope indeed.

11. In addition to genuine compassionate concerns about affected families there are very powerful ideological and financial vested interests in this field including research grants for scientists, profits for biotechnology companies and prestige for the British government. 

12. Hard cases do not necessarily make good law or policy. I remain deeply suspicious of the way this 'breakthrough' that will potentially help only a tiny number of people with a very limited number of conditions is being  foisted on the British public using emotive personal stories by an incredibly well-organised coalition of politicians, biotechnology companies, journalists, research scientists and patient interest groups without full consideration of the concerns like those above which many have expressed. I suspect there are much bigger agendas here that are not yet being fully disclosed. Are we, for example, seeing reproductive cloning and germ line therapy being deliberately smuggled in under the back door under the guise of compassion? The moving boundaries and mission creep we have seen with other IVF-related technologies should sound a huge note of caution for us. 

I have written previously on mitochondrial disease here, here, here and here. Also see CMF’s official submissions to the HFEA and Nuffield consultations on this issue and  a recent blog post where we argue that these techniques are unsafe, unnecessary and unethical.