Good facts are essential for good ethics, so first here are some simplified facts about creating three genetic parent children.
A woman’s ovum (egg) has a nucleus with 23 chromosomes (half the number of chromosomes in all other human cells). A man’s sperm likewise has 23 chromosomes. When the sperm fertilizes the ovum the female and male chromosomes recombine in a stunningly complex process to form a human embryo as a genetically unique new human being (the embryo might later split to form identical twins or triplets).
These recombined chromosomes from the mother and the father are the DNA of the nucleus of that embryo. But the embryo also has a small percentage of its DNA in the cell cytoplasm that was part of the ovum and surrounds the nucleus of the embryo. This is the mitochondrial DNA (mtDNA) which is inherited only from the mother and does not undergo recombination. (This means mtDNA is passed largely unchanged from generation to generation and, therefore, can be used to trace one’s ancestors.)
Mitochondria, which contain the mtDNA, convert chemical energy from food into a form that the embryo can use. Sometimes, however, the mtDNA is genetically faulty and the mitochondria cannot do this and the embryo dies.
The mitochondria replacement intervention involves replacing the mother’s faulty mtDNA with healthy mtDNA from another woman, the donor, which results in an embryo with three genetic parents, two women and one man.
The ethical issues this procedure raises are many and complex and can only be briefly mentioned here.
First, the source of the healthy mtDNA can be either a donated ovum or embryo. The nuclear DNA of the healthy donated ovum or embryo is removed and replaced with the nucleus of the wanted ovum or embryo.
There are ethical concerns about risks to and exploitation of women donating ova, but the use of an embryo is far more ethically confronting. It involves intentionally killing one embryo to make another viable.
In one version of this technique, the father’s sperm is used to fertilize the mother’s ovum and the donor’s ovum – that is, two embryos are intentionally created. The nuclear DNA is then removed from the donor’s embryo and replaced with the nuclear DNA of the mother’s embryo.
Using cytoplasm with healthy mtDNA from IVF embryos which their parents don’t want – so-called “spare” or “leftover” embryos – is also a possibility. Those who approve of this argue that these embryos may be used because they will die anyway.
But natural death differs ethically from intentionally inflicted death and being used just as a means to help someone else does not respect the human dignity of the embryo.
Then, the risks to the “wanted” embryo are very uncertain as having three genetic parents is unprecedented. Also, there are risks intrinsic to the procedure itself. For example, it’s been found that defective mtDNA can be accidentally transferred with the nucleus of the mother’s ovum or embryo.
If we believe that it is inherently unethical to use technology to design the very essence of our descendants, then we would reject this intervention.
The reasons given by German philosopher Jurgen Habermas for taking this stance are worth noting. He explains that such interventions contravene both the liberty and equality of the “designed” person, because the person is not free to create their own authentic self as this requires having “non-contingent origins”, and they are not equal because the designed person is not equal to the designer.
People who oppose such interventions are likely to describe them as manufacturing a human being and would be worried about the precedent which allowing them sets that designing our children with even more radical technologies (such as altering the human germline – the nuclear genes passed from generation to generation – for example, with CRISPR cas9) is ethically acceptable.
Major international institutions, for instance, UNESCO, World Health Organisation (WHO) and the European Parliament have spoken out against allowing any genetic modification that would be passed on to future generations as contravening human dignity and there are calls for such interventions to be universally prohibited. Mitochondrial replacement is such a technology as the genetic changes it effects would be passed on.
In short, people who oppose such interventions are concerned, not just about the risks and harms for the individuals involved in using these technologies, especially the resulting child, and not only their impact in the present, but also are concerned about protection of the “common good” and the welfare of future generations, including the “ethical tone” of the societies which would result. Might they be societies in which no reasonable person would want to live?
In contrast, as has been accepted in the United Kingdom, but not yet implemented, utilitarians would allow three-parent children on the grounds that mitochondrial replacement does more good than harm and reduces the suffering of infertile people longing for their own genetically related children.
As is true for most and probably all arguments for so-called “progressive” values, the proponents of mitochondrial replacement technology use concealing and euphemistic language to describe what is involved and employ familiar analogies.
So, for example, they point out that we approve of organ transplants to save lives and argue that mitochondrial replacement is just a transplant of a very small amount of genetic material to save the life of an embryo. They fail to recognise that in contrast to other transplant situations the existence of the embryo with defective mtDNA, thus needing a transplant, was intentionally created. They also downplay the impact of mtDNA arguing that it just facilitates the development of the embryo and does not determine the resulting human being’s fundamental features. As well, they point out the percentage of genes in the mitochondria is tiny compared with the embryo’s total number of genes – an argument along the lines of “de minimis non curat lex”, the law does not concern itself with trifles.
It is also relevant to keep in mind that the “Infertility Industry” is a multi-billion dollar enterprise worldwide. It operates through very attractive marketing campaigns featuring beautiful babies and adoring mothers – and occasionally handsome fathers, when speaking to a gay male audience. It’s difficult not to associate it with the advertising of luxury consumer products, whether a Fendi or Hermes handbag, or perhaps a Ferrari, which are meant to elicit the response, “I want one of those”.
But a baby is not a handbag or a car and it should not be either manufactured or treated as a product.
What might asking ourselves how we should fulfil that requirement not to objectify a child tell us about how we should govern the use of mitochondrial DNA replacement technology and other such procedures? For example, would it be ethically acceptable to create a child with the genetic inheritance of two men or two women? Animal experimentation is showing that this will become possible.
So, as renowned Australian scientist Professor Alan Trounson said to me when the existence of Dolly, the cloned sheep, was revealed, “Margo, it you want to know what will be possible, look at what we are doing in animals now and seven years down the line we will be able to do it in humans.”
Margaret Somerville is professor of bioethics in the school of medicine at the University of Notre Dame Australia. This article was first published in The Catholic Weekly (Sydney).