news & comment
three-parent embryos
Can the ends ever justify the means?
see the full story at cmf.li/411UlyU
Every year, about 1 in 5,000 babies are born with a mitochondrial DNA (mtDNA) mutation, inherited from their mother, leading to incurable, life-changing, and often life-shortening diseases.
In 2015, the UK licensed an in vitro fertilisation (IVF)-based technology, known as ‘pronuclear transfer’. This involves the fertilisation of an egg containing disease-causing mtDNA and a donor egg with unaffected mtDNA. The nucleus from the unaffected zygote is then removed and discarded and replaced by the nucleus from the affected zygote. The resulting embryo thus inherits its parents’ nuclear DNA, and mtDNA from the egg donor – technically a three-biological-parent embryo. 1
In 2013, Philippa Taylor wrote about this technique: ‘It may be that one day, some children might be born with three genetic parents. If so, we must treat them with the compassion we would show to any other human being. But it would seem wiser, given the scientific uncertainty, ethical problems and availability of alternative approaches, if we did not take a further step down that road.’ 2
Under Prof Sir Douglass Turnbull, a reproductive care pathway to provide women carrying pathogenic mtDNA variants with reproductive options, including mitochondrial donation, has been set up in Newcastle. Their results were published in July 2025 in the New England Journal of Medicine. 3 A total of 22 women with pathogenic mtDNA commenced or completed the process. There have been eight live births, including one set of identical twins. All eight children were born healthy, with no or low levels of mtDNA heteroplasmy detected in their blood. All are enrolled in an 18-month developmental study, and at the date of reporting, all the babies were meeting their relevant developmental milestones. The research team will continue to offer assessments up to the age of five years.
It would be hard to overstate the joy and relief these children have brought to their parents, or the hope they represent to more couples living with mitochondrial disease. Should all continue to go well, it seems likely that mitochondrial donation will become more widely available in the UK.
But is this a cause for undiluted rejoicing, a triumph of technology over the devastation of some rare inherited diseases? Or are there concerns we should not overlook amid all the backslapping?
While 22 women underwent mitochondrial donation through pronuclear transfer, only seven of them had live births, a success rate of 36 per cent. IVF in general has a success rate of just 31 per cent, so based on efficacy alone, it would be difficult to withhold or restrict the availability of pronuclear transfer procedures. But what of the 64 per cent unsuccessful outcomes? Further research is needed, but it’s already clear that the technique can’t currently promise success for the majority of those who want it.
Secondly, and of greater concern, the procedure creates two embryos, but not with the intention of both being welcomed. The process is destructive, as only the composite embryo will ever be offered hospitality and nurture. For those who believe that human life begins at fertilisation, the destruction of human life at any stage of development is ethically unacceptable.
Next, the procedure suggests that the end justifies the means. It never does. It is not possible to add together two ethical ‘wrongs’ and make one ethical ‘right.’ Noble work must be achieved by noble means. The alleviation or prevention of disease and suffering is a noble aspiration, but not at any price, and certainly not if it entails the deliberate destruction of another human life. Pronuclear transfer involves wasting some embryos to create others. This surely commodifies human embryos.
A child is a gift from God, a mysterious bundle to be accepted and cherished, not a made-to-order acquisition. The Christian gospel declares that a person’s worth depends not upon their abilities, achievements, or productivity, but upon their being made in the image of their Creator.
Finally, pronuclear transfer undermines a key pillar of marriage – that it is an exclusive relationship between one man and one woman – by introducing a third party into the marriage.
Looking further ahead, what happens when the three-parent child reaches late teens and wants to know the woman from whose enucleated egg they were formed? Currently, the HFEA does not disclose that information. But surely the adult child should have the right to know their genetic heritage? Once again, the emotional and psychological impacts on recipients, donors, and their families are complex.
Other avenues can be tried. Maternal spindle transfer (MST) 4 has been suggested as an alternative method to avoid transmitting mitochondrial diseases. The procedure has the ethical advantage of transferring eggs rather than embryos.
Alternatively, adoption is a mutually beneficial act that provides a loving home for a child who is already in need, while allowing childless couples to experience the loving service of parenthood.
We rejoice with those who cherish the children they had almost lost hope of having. But perhaps we should also tremble as we take yet another step in the direction of commodifying children and introducing germline therapies, straining for biological perfection in the attempt to eradicate suffering by any means.
Rick Thomas was the Public Policy Researcher at CMF
references (accessed October 2025)
- Mitochondrial donation treatment. Human Fertilisation & Embryology Authority. bit.ly/42dPtqV
- Taylor P. Three-parent embryos for mitochondrial disorders. CMF file 51. 2013. cmf.li/4gBt5h2
- Hyslop L. et al. Mitochondrial Donation and Preimplantation Genetic Testing for mtDNA Disease. N Engl J Med. 16 July 2025;393:438-449. DOI: 10.1056/NEJMoa2415539
- Op Cit. Human Fertilisation & Embryology Authority
assisted suicide bills
what happens next?
see cmf.li/AssistedSuicideResources for more information
It’s been a busy year in the attempt to legalise assisted suicide for the terminally ill in the British Isles. The Isle of Man’s parliament, the Tynwald, agreed a law to allow terminally ill adults to be assisted to end their own lives in March. There is a five-year residency requirement to reduce the risk of ‘assisted suicide tourism’, but the bill is still awaiting Royal Assent to become law.
In May, Holyrood voted the Assisted Dying for Terminally Ill Adults (Scotland) Bill through to the committee stage for consultation and amendments. This vote was on the principle rather than the wording of the Bill, and there are likely to be further amendments and debates before it comes back for the third stage reading, probably this autumn. Committee hearings will start and are expected to conclude in November. However, there are also questions about the devolved or reserved competence in the Bill – ie will passing it in Scotland have impacts across the UK that come under Westminster’s jurisdiction. This may not be resolved before Holyrood rises for the 2026 elections in March.
The Terminally Ill Adults (End of Life) Bill for England and Wales similarly passed through a committee stage that many MPs criticised for being rushed and inadequate; yet it was still voted through (albeit with a significantly reduced majority) at third reading in June. In a strong debate in the House of Lords in September, its opening reading in the Lords in September had so many peers wanting to speak that it had to be held over two consecutive Fridays. While it was passed through to the next stage, two-thirds of speakers expressed dismay at how badly drafted the legislation was. Even some of those who agreed with the principle were unhappy with it as it currently stands. Taking the unusual step of calling a Select Committee, there will now be a further stage of gathering expert evidence, including from many of the professional bodies that were excluded from the Commons parliamentary committee.
Where does this leave us, and what can we do? The Isle of Man legislation still hangs in the balance, but could receive Royal Assent shortly, but how many people will ever take advantage of its provisions is hard to say. With a population of only 84,000, the number of eligible patients is likely to be very small.
If you live in Scotland, you can still write to your MSPs to express your concerns as a health professional and arrange to meet with them to explain why they should reject the Bill at the third stage. It is still possible that this Bill could fail at the next stage.
In England and Wales, you can write to any members of the House of Lords and raise your concerns. On the CMF website, a detailed briefing is available on how to do this, 1 along with two in-depth briefing papers for peers on the dangers inherent in the Bill. 2,3 Again, there is still a chance for this prospective legislation to be thrown out at this stage.
As before, your contributions, both in writing and in person, with your representatives, have had a significant impact in swaying many legislators to change their votes. Do not underestimate the impact of your voices, and above all, your prayers, in these debates.
You can join daily prayer meetings about all these pieces of legislation at 9 pm UK time via cmf.li/Pray4ASbill
Steve Fouch is CMF’s Head of Communications
references (accessed October 2025)
- Leadbeater Bill in the House of Lords. CMF. August 2025. cmf.li/HoL-AS-25
- Myers K, Lamb E, Anthony Pillai R. ‘First Do no Harm’: Concerns from senior doctors regarding the Terminal Ill Adults (End of Life) Bill. August 2025 cmf.li/4o2abCv
- Protecting patients from assisted suicide. Christian Institute and CMF. February 2025. cmf.li/PPA
