“This does not threaten the fabric of our society in any way whatsoever: it’s an individual choice for someone who’s watched a child die of a horrible disease”.

For Robert Winston, a pioneer of IVF and one of the country’s most famous doctors, the recent decision by the House of Lords to approve the creation of babies using donated mitochondria was an emotive one.

“Most children with Leigh’s syndrome, for example, go floppy, go blind, have fits, have steady brain deterioration and die by the age of 2. The few that survive will have muscle weakness and muscular dystrophy and blindness.

“The one thing worse than losing your own child is losing your own child after a hideous disease.”

Mitochondria are structures in every cell that produce ATP, the molecule that powers chemical reactions within the body. Genetic mutations, however, can cause mitochondria to work ineffectively, causing these severe illnesses.

In the new technique approved by parliament, the nucleus of a fertilised egg is removed and implanted in the cytoplasm of a donor egg from a healthy woman.

It’s been described in the media as creating “three-parent babies”, but it’s not a term Winston especially likes.

“When I’ve had a blood transfusion, I got far more foreign DNA in my body than any ‘three-parent baby’ would have, so the name is nonsense, obviously. Admittedly, it’s permanent, but it’s a permanent cure, unlike my blood transfusion, which will only cure my anaemia for a few weeks”.

The vote enjoyed broad support in the Lords, passing with a majority of 232. The decision has been severely criticised by the Catholic church, however, and in the preceding debate, several members criticised the treatment for ethical and safety reasons, as well as for the speed with which the decision was being made.

Lord Winston was one of the most vocal supporters of the treatment in the debate, and was particularly critical of those opposed on religious grounds, and was keen to emphasise the ethical principles that had influenced his decision.

“I think that in a pluralistic, democratic society, responsible individuals should have their autonomy respected, and I don’t think it’s any business of parliament to say: “yes, you should have this treatment” or “no, you can’t have this treatment”.

“My impression of the women who want this treatment was that they were requesting it because they did not want to have a termination of pregnancy, because they thought this was morally wrong, so it seems to me to be utterly wrong for a parliamentarian who’s opposed to abortion, for example, to get up and impose their view about somebody, who doesn’t want abortion either, but actually wants something which is a lesser injury, which is to get rid of the damaged egg.

“The mitochondrial diseases that affect child-bearing families are actually pretty rare, so this regulation would only apply to a few families.

“Essentially, I think there are four principles we must consider ethically: one is the respect for the autonomy of the individual, who’s requesting something, and that means informed consent, so you listen to their problems and you explain the difficulties and the dangers to them, and that you respect their confidentially, which is quite important, and you respect their opinion. Now occasionally, of course, it might be that, for example if I was a religious Catholic, I might disagree, in which case, the correct thing for me to do would be to send them to another doctor.

“This is not a diatribe against Catholics. I deeply respect Catholicism, but I think nonetheless, it’s important that we don’t try and impose our minority view. I’m a Jew, and I wouldn’t dream of imposing a Jewish view on someone with mitochondrial disease. Actually the Jewish view would be to treat them, although I don’t think many rabbi’s have really spoken about it particularly.

“So the first thing is the autonomy, the second thing is that it is encumbered upon us to be beneficent, to try to do good, and to my mind, if you can prevent a child dying horribly, and having a healthy life in consequence, that’s beneficent. The main thing is not to do harm, so you’ve got to look at the side effects, and after the extensive research done in Newcastle, I’m fairly happy that the chances of serious side effects are much less than the benefits.

“Lastly is the issue of justice: what’s the just solution for these people? The just solution for them is to have the treatment they think they need”.

Despite the vote, Winston says the first baby born in the UK through this method is still a long way off.

“What will now happen is that any person who thinks that they may have mitochondrial disease and doesn’t want to watch their baby die can apply to a unit that’s prepared to do this treatment, and this unit can then apply for a license to the regulatory authority, the HFEA (Human Fertilisation and Embryology Authority).

“That authority will take into account a whole range of things including their expertise, the kind of research they’ve done, the kind of precautions they’ve taken and they may or may not grant a license, but it will probably be done on an individual case by case basis.”

In the late 90s, Jacques Cohen and his team in New Jersey developed a similar technique to implant healthy mitochondria into embryos. They were trying to allow older mothers who had struggled to conceive a way to have healthy children. 17 babies were born, and while two had chromosomal defects, this may have been due to the age of the mother, rather than the treatment.

Despite the early promising results, mitochondrial replacement has been banned outright by the US Food and Drug Administration since 2002 because of safety and ethical concerns.

“I don’t know whether it was the right decision,” says Winston. “I think since then there’s been a lot more research into trying to do nuclear replacement and spindle replacement in human embryos. The problem, of course, is that there isn’t an animal model for mitochondrial disease, so you can’t test this in a cow, for example, and see whether it will have an effect.

“One of the issues I think about mitochondrial disease is that there may be a nuclear DNA component, so these people with mitochondrial disease might not only have mitochondrial mutations, but also mutations in the DNA of the nucleus, which you’re not treating. So it could be that they may be still affected by the disease, but less so.

“Of course there’s a risk of something going wrong with any treatment, and don’t forget that when we did IVF for the first time, we were actually standing on the edge of a precipice: we had no idea for certain that we were going to have a normal baby, although all the experiments that had been done would suggest that.

“Our lab at Imperial did the first pre-implantation diagnosis, actually biopsying a cell, taking cells away for genetic analysis. That had never been done before, so, even though we had tested it in various animals, again, it’s a leap in the dark, but you know you had done the best you could.”

The decision has generated a huge amount of media coverage, much of which has been focused on the ethical criticisms levelled by many opponents and religious groups.

“I think the media coverage has been pretty gentle really,” said Winston. “The ‘three-parent family’ level was inevitable, and it’s a silly label, but it’s a convenient piece of shorthand. But actually, very few journalists produced shock horror, and I think journalists talked it up because they thought it was going to be very big.

“To tell you the truth, I think the media coverage for a huge number of scientific things has improved massively in Britain over the last 5-7 years. You see it even in the biggest comic of all, the Daily Mail, which is classically the one newspaper you would not regard as scientific journal: don’t forget that when the Japanese nuclear accident happened, Mike Hanlan, the chief scientific correspondent of the Mail was very measured in what he said about Fukushima. He said this was not a cause for abandoning nuclear fission, this was an aberrant response to an aberrant piece of building, and even beforehand we could have realised we were doing something that was probably not wise.

“I think actually, Mike Hanlan’s response in a tabloid newspaper was highly refreshing, and is somewhere I think even 10 years ago, we would have had a much more aggressive, much less measured view. I think British scientific journalism has improved immeasurably and I think, actually, to some extent, that’s had a knock on effect right through to the sort of journalism that you do in Felix.”

The media coverage of the decision has highlighted the important relationshiop between science and politics, and raised questions about where genetic treatments could lead.

In the future, germ-line gene therapy could treat diseases such as cystic fibrosis, by replacing faulty segments of nuclear DNA in the genome of a fertilised egg. The research is at a very early stage at the moment, and concerns over safety and ethics are much more profound than for mitochondrial transplants.

“I wouldn’t be happy with germ-line gene therapy, because I think the problem with that is that you are very likely to have an effect on other loci in the genome, which may start to perform differently from what you expected, because, as we know, upstream and downstream of any mutation, there will be other signalling areas of the genome, micro RNAs for example, which may actually end up producing something which is completely unexpected. The likelihood with mitochondria is that, because their role is so specialised (they’re really just concerned with energy metabolism) that it’s a reasonable gamble, if you like.

“I don’t see anything wrong with playing God. To my mind, if you are religious, playing God is what you should do, because actually what I believe is that if you are playing God you are actually imitating God, using your God-given intelligence to try and better the world.

“The issue then is not playing God, but trying to supplant God, which becomes much more an issue of how you use wisdom and judgement to make a good choice rather than a bad choice, and I think that’s what we all do as scientists all the time, which is a universal concern for all of us at Imperial College.

“If you’re doing physics, for instance, there’s all sorts of implications, medical physics is a good example, nuclear physics would be another one. There are times when physicists have stood back and said, well actually this may be going in the wrong direction, because we’re doing something which we feel very uncomfortable with.

“So I think making a wise choice is right. Now of course with hindsight you could say that perhaps Oppenheimer, say, made the wrong choice in making the atomic bomb, but of course that was at a time of conflict when there were very different issues going on.

“In peacetime, during the normal workings of a democratic society, that wisdom of how to make the best choice is part of what we have to do as scientists: that’s why I think we need to be very much more aware of a breadth of knowledge, not just knowledge of a narrow area of our own discipline, and to my mind, one of the things we have to do as scientists is to keep aware of the broad implications of the work we do.”