Conversations around fertility are tricky. The desire to have a child who carries on one’s line is strong and deeply rooted. And the anguish caused by the risk of passing on a serious genetic disease can be as deep as being unable to conceive naturally. So compassion for those who face this harrowing situation is vital – but so is a clear-eyed view of what certain technologies mean for our society.
The world has recently seen the advent of several Artificial Reproductive Technologies such as In Vitro Gametogenesis, Synthetic Embryos and Artificial Womb Technology. Regardless has explained these, and covered their ethical implications here.
In one of the world’s latest ART breakthroughs, the media is now heralding “three-parent babies”, enabled through mitochondrial replacement therapy (MRT).
What is Mitochondrial Replacement Therapy?
Every person’s cells contain mitochondria – tiny batteries that convert food and oxygen into the energy that keeps the body alive. Mitochondria come with their own set of genes, all passed down only from the mother. When these genes are faulty, children can inherit severe diseases that damage muscles, the brain, heart and other vital organs.
Mitochondrial diseases are rare, affecting perhaps one in every five thousand births. But they are also devastating, often leading to disability or early death. MRT therefore targets a very small group of families facing great suffering.
MRT is an IVF procedure designed to avoid passing on those diseases. The idea is simple: keep the DNA from mum and dad, but swap out the mother’s unhealthy mitochondria for healthy ones from another woman.
Here’s how it works in simple english:
Pronuclear Transfer
Doctors start with eggs from both the mother and a healthy donor.
In one method, called pronuclear transfer, both are fertilised with the father’s sperm. The genetic material from the parents is moved into the donor’s embryo, which contains healthy mitochondria. The donor’s own genetic material is discarded.
In effect, one embryo is created and then discarded so that another may live. This raises serious ethical questions around treating human beings as means rather than ends, even if MRT might present a solution to a couple’s problem of heritable disease.
Spindle Transfer
Another method, spindle transfer, takes the mother’s nuclear DNA and places it inside the donor’s healthy egg before fertilisation.
The resulting embryo has more than 99.9% of its DNA from the parents, but about 0.1% – the mitochondrial DNA – from the donor which does not affect traits like looks or personality. Any daughter born this way would pass those healthy donor mitochondria to her own children, making the change permanent in that family line.
Safety Remains Unsettled
In 2021, the Bioethics Advisory Committee advised against permitting MRT, citing insufficient safety and efficacy data. This was not a dismissal of parents’ hopes, but a recognition that some lines in medicine should be crossed only when evidence is strong and risks are low.
Eight live births in the UK do not prove safety; a few early successes cannot replace robust, long-term data. As yet, no MRT-conceived children have reached adulthood.
We do not know the long-term effects, and trials have recorded “reversion,” where defective mitochondria from the mother reappear despite the transplant. This happened in three of eight cases among the 8 UK births with between 5-20% of mitochondria being defective in blood and urine samples.
Without decades of follow-up, safety remains an open question.
In fact, there is a real risk that by solving for one potential health problem, MRT inevitably creates more health problems down the line. Professor of Mitochondrial Genetics, Joanna Poulton, emphasised that the nuclear transfer process and laboratory manipulation might induce a reorganisation in cellular structures and impact early embryo development.
Other commentators have raised concerns around potentially altering epigenetic marks. In simpler terms, this means the lab process could switch certain genes on or off in unexpected ways, changing how the embryo develops or functions later in life.
Still other experts have highlighted that there could be mismatches between nuclear and mitochondrial DNA, leading to metabolic disorders, as mitochondria play a critical role in energy production.
As it stands, ethical considerations aside, the science is far from settled.
The Cost to Human Life
MRT involves creating and destroying large numbers of embryos. In the UK’s first reported live birth via this method, one MP noted that 316 embryos were created and destroyed to achieve that single outcome.
Although CNA’s commentator would like to construe this as a matter of private belief or faith, it is actually a matter of universal human rights.
Each embryo is a human being in its earliest stage, just as a toddler or an elderly person is human at a later stage. Accepting such losses as routine normalises the idea that some human lives can be treated as expendable raw material for others.
A Door to Modern Eugenics
History has shown eugenics to be harmful and dehumanising, reducing people to the value of their genes and undermining the equal worth of all human life.
That is not a road Singapore should go down, even if we may have set foot on the path before.
MRT embeds that same mindset. It treats embryos as selectable, discardable material, and can pave the way for normalising human reproduction as something to be engineered and optimised.
Once embryo manipulation is accepted for one purpose, it becomes harder to resist for others—selective breeding pressures, genetic trait selection, and a gradual erosion of respect for all stages of human life.
Accepting such interventions now, even in the name of compassion for those with rare diseases, risks habituating society to the logic that some lives are worth creating and others are not.
That is the gateway through which eugenic thinking enters.
Autonomy and consent
Respecting the autonomy of individuals is a fundamental ethical principle.
The child that is born through MRT cannot provide consent for the procedure that affects their genetic makeup. In MRT, the future child’s autonomy is compromised because they cannot choose whether to undergo the procedure. This raises ethical questions about making irreversible genetic decisions on behalf of someone who cannot participate in the decision-making process.
It also alters the germline permanently. Heritable mitochondrial changes are passed down to future generations, reshaping the genetic line of an entire family.
This matters because such irreversible changes can create future liabilities: children and grandchildren may face unexpected medical complications, insurance and healthcare systems may bear unknown costs, and legal disputes could arise over responsibility for harms that only manifest decades later.
In other words, what looks like a private parental choice today can generate broad, long-term disadvantages for families and society tomorrow.
The Human Side of Having Three Genetic Contributors
Even if the mitochondrial donor’s DNA makes up only a small fraction, the contribution is real.
Biological links carry deep personal meaning. We already know through the shared experience of many donor-conceived children that they grow up with a strong desire to know their biological (donor) parent, often struggling with feelings of incompleteness or confusion.
What happens when there are three contributors?
How might it shape a person’s sense of self to know they “owe their health” to someone outside their family? What then are the duties and responsibilities that accrue?
The psychological impact may be magnified by the knowledge that this genetic input was deliberately engineered. Many people need to feel that their origins are natural, not manufactured. When life feels more like a product of laboratory design than a gift, it can weaken one’s sense of authenticity and belonging. That loss of the “natural” can translate into struggles with identity, dignity, and self-worth.
These questions, far from being abstract, reach into the deepest layers of identity and belonging in a very practical sense.
Compassion with Caution
The desire to help those with rare mitochondrial diseases is genuine and noble. But pragmatism cannot be our only guide. Not every door of scientific possibility should be opened simply because it exists. The road to hell, as the saying goes, is paved with good intentions.
The path from medical treatment to genetic design can be short and silent. MRT’s promise must be weighed against the irreversible ethical costs it carries. Where the risk of passing on dangerous genetic code is high, ethical alternatives such as fostering or adoption can still honour the deep and legitimate longing for children without crossing lines that future generations may regret.
Singapore’s cautious approach has served it well. Before we step into this territory, we must be certain it will not lead us somewhere from which there is no turning back.
