In early February 2015, MPs voted to amend the 2008 Human Fertilisation and Embryology Act to permit mitochondrial donation (Gallagher, 2015). On 24 February, the House of Lords approved the amendment, and it will be enshrined in law in October 2015. This makes Britain the first country to address the problem of mitochondrial disease by allowing the creation of babies by IVF using biological material from three different people.
The decision has prompted controversy. Before considering the ethical aspects of mitochondrial donation, it is perhaps worth asking what are mitochondria, what is mitochondrial disease and what does the mitochondrial donation technique involve?
The mitochondria are organelles that generate most of the cell's energy. Numbers of mitochondria per cell vary from zero to hundreds or thousands. Mitochondria hold around 0.1% of a cell's DNA, and this mitochondrial DNA (mtDNA) comprises 37 genes (Amato, 2014). Unlike the genome in the cell nucleus, which includes maternal and paternal DNA, all of a person's mitochondria stem from the mother's egg (Calloway, 2014).
According to the Department of Health (2012), the symptoms of mitochondrial disease—which is incurable—include poor growth, loss of muscle coordination, visual and hearing problems, mental disorders, heart disease and liver disease. In the UK, around 12 000 people live with mitochondrial disease; it affects one in 5000 adults; and one in 6500 babies is born with a severe form of the disease that can result in death during infancy.
Mitochondrial disease can be due either to mutation in mtDNA or mutations in nuclear DNA involved in mitochondrial function. This first form of mitochondrial disease could be averted through one of two techniques: pro-nuclear transfer or maternal spindle transfer. Pro-nuclear transfer entails genetic material from both parents contained in the pro-nucleus being removed from the fertilised egg before it has developed into a multi-cell embryo. This is then transferred to a fertilised donor egg that has had its own pro-nucleus removed but which contains healthy mitochondria (Torjeson, 2013). Maternal spindle transfer involves removing the mother's nuclear DNA from one of her eggs and transplanting it into a donor's egg containing healthy mitochondria but from which the donor's spindle has been removed. This egg is then fertilised with the father's sperm.
The ethical debate
At the cutting edge of mtDNA donation technology is a Newcastle University team who have received £4.4 million in funding from the Wellcome Trust. So the technology is available, but the ethical issues surrounding the topic continue to be keenly debated. Calloway (2014) cites the Conservative MP Jacob Rees-Mogg, who, during a Parliamentary debate last year, equated mitochondrial replacement with cloning and summoned up the spectre of eugenics: ‘In a country nervous about genetically modified crops, we are making the foolhardy move to genetically modified babies.’
Genetically modified, or so-called ‘designer babies’, are said to form part of the slippery slope at the top of which mtDNA donation is alleged to rest, and many critics assert that there is something ‘unnatural’ about the process. In a poll carried out in the early 1980s in Australia, the most common reason given for opposition to the technique was that it was thought to be unnatural (Ball, 2014). Ball also cites the observation of geneticist JBS Haldane who, in 1924, said: ‘[t]here is no great invention, from fire to flying, which has not been hailed as an insult to some god. But if every physical and chemical invention is a blasphemy, every biological invention is a perversion.’
Another point raised by critics is that mtDNA donation results in the destruction of embryos. This is true in the case of pro-nuclear transfer, but not with the maternal spindle transfer technique.
The phrase ‘three-parent babies’ has become central to the current debate, with some saying that if a third party has contributed DNA—no matter how small—to the creation of a child then she is also a parent. This point is significant to the extent that British law confers on those born as a result of egg or sperm donation the right to know who their biological parents are. However, the draft regulations currently grant anonymity to mtDNA donors. It can be argued that the donated mtDNA comprises a tiny percentage of the embryo's complement of DNA and does not code for essential characteristics. This is true…up to a point; however, the one essential characteristic contained in the donated mtDNA ensures that the baby will be born free of mitochondrial disease. In those circumstances, might an adult who had been born through mtDNA donation not be entitled to know who the person was whose tiny amount of DNA made such a profound impact on his or her health?
Irrespective of competing arguments, it seems that midwives will soon be delivering babies free of mitochondrial disease, which might otherwise have disabled or killed them. As for the long-term consequences… who knows?