The idea of children born of three parents smacks of science fiction. We may well feel that, by comparison, minor tweaks in the DNA of the embryo are small beer. Yet it is a real and immediate prospect allowed by an amendment to British law. Currently the Department of Health has issued draft regulations for its introduction and is requesting reviews from “stakeholders” and the wider public. That means us. So what are we going to do about it?
This is an introductory guide which I hope will lead you study the material.I will, of course, be focusing on the questions which interest us as Catholics. As the survey only addresses draft regulations, opportunities to express our views are limited.
The human cell contains two sets of DNA. The first is the DNA which carries our personal characteristics (nuclear DNA). At conception, the mother and father’s DNA combine a new mix of their DNA to be the “blueprint” for the baby. In turn, this blueprint will be inherited. The second is mitochondrial DNA. This does not contain personal characteristics but provides most of the cell’s energy. They are sometimes called the “battery pack”. They represent a 10th of one per cent of the total DNA, and they are believed to be of bacterial origin. Only the mother’s mitochondrial DNA are passed on to the child. Faulty mitochondria can cause widespread damage because they affect cell function. The list of disorders which may be caused is long and frightening. There is no cure. As a parent of 21 healthy descendants, I blanch when I read it.
In some cases the effect can be mitigated by implanting only the healthiest embryos, or by aborting damaged foetuses at a later stage. But, in more complex cases, another solution – still at an experimental stage – may be proposed. It is possible to remove the faulty mitochondria and to replace it with healthy mitochondria from a donor. There is good evidence that this will work well and safely, but ultimately only long-term experience of use will tell. Two processes are envisaged.
The first (maternal spindle transfer) is to take the mother’s personal DNA from her egg, and to insert it into the donor’s egg (from which the donor’s personal DNA has been removed). The egg is then fertilised. The second (pro-nuclear transfer) involves inserting the maternal and paternal elements from a fertilised egg into a healthy donor embryo from which the corresponding elements have been removed. The transfer takes place during the process of fertilisation but before the parental elements have fused. In either case the resulting child will have three DNA sources: mother, father and donor. In both procedures the donor’s mitochondria will enter the germ line: it will be inheritable.
In reviewing the moral aspect of these processes, we must start by accepting that the immediate benefits of successful mitochondrial replacement are potentially large. It is estimated that there would, at least initially, be no more than 10 eligible cases a year, but these could be 10 tragedies averted. But there are alternatives: adoption, donor eggs (with its own moral questions) and simply accepting the vocation of childlessness.
The issue of a child with three parents immediately comes to mind. But it is argued that this reaction is not justified. Since mitochondrial DNA has only mechanical effects and conveys no personal characteristics, the idea of an additional parent is unwarranted. Yet many will be concerned with foreign DNA being introduced into the germ line and remaining there indefinitely. And can we gauge the long-term effects of such a novel and extreme procedure through future generations?
The “slippery slope” argument will certainly be a consideration. While mitochondrial transfer is altogether different from inserting personal DNA, it can be argued that accepting the alteration of the germ line opens the door to unfettered genetic manipulation. Defenders of the procedure are quick to point out that, if it is not available under what will be our carefully considered legislation, it will certainly be available in other countries, and probably in unrestricted and questionable ways.
The procedures themselves raise moral questions. Both require removal of the ova from the reproductive tract and artificial insemination. The pro-nuclear transfer requires the manipulation of a fertilised egg – but one in which the blueprint DNA of the new baby has not yet formed. Thus it would seem that it does not yet constitute a human individual. Thus it would seem that it does not yet constitute a human individual. But the general prohibition of interference with the process of human reproduction would be breached.
You may be helped here by reference to the Catechism, remembering, of course, that this precise procedure was not considered at the time of drafting, nor was a distinction made between the start of the fertilisation process and the point at which the parental DNAs are fused (approximately 24 hours). Paragraphs 2376/7 address the issue of dissociation of the sexual act from the procreative act. This intervention alone may be sufficient to settle the question for many, but others might argue that the therapeutic intention of the procedures provides justification. The fact that the Church’s views on this may not be persuasive in the public forum should not prevent us from expressing them.
The link below will take you to the D of H enquiry. The other link will give you further information, including an excellent discussion of different ethical views.