If I were choosing a third parent for a baby, you know, I’d be inclined to choose one of the Williams sisters — the top-notch tennis players. If you want to create a baby with really classy metabolism — and metabolic function is just what the third parent provides — you may as well make it good. But what you can’t do, in creating a baby that’s able to process energy efficiently, is pretend that this is anything other than genetic modification.

Yet the Department of Health, in effectively approving the three parent baby technique (actually, it’s always going to be two mothers plus one father), has redefined its categories in its proposals to allow mitochondrial DNA transfer. The proposals were published this week. If parliament approves the measure — and it’s unlikely that it won’t, given the inability of British parliamentarians to engage coherently with questions of moral philosophy — then it would make Britain the first country to allow three parent babies.

Characteristically, the BBC, in its interesting Radio 4 PM programme yesterday, engaged with the human aspect rather than the moral issues. It ran an interview with Liz Curtis, whose daughter Lily was a victim of mitochondrial disease, and very moving it was. Mrs Curtis is fully entitled to be an advocate for a change in the law but her arguments, perhaps inevitably, went almost entirely unchallenged. She observed that the technique was a bit like taking the yolk from an egg and just transferring it to another egg, and maintained that the technique didn’t involve any of the DNA that makes us what we are. It hardly merited the term ‘third parent’, she said.

Well, I’m sorry, but a second mother is exactly what the process provides. The technique inserts the fertilised nucleus from one egg with tainted mitochondria into another egg from which the nucleus has been removed. While the nucleus provides overwhelmingly the greater part of the genetic material in an egg, it constitutes only about half of the bulk of the ovum. The DNA in the mitochondria — the egg white, using Mrs Curtis’s analogy — is not negligible. It affects how efficiently we process energy, which is quite an important element of the DNA that we are going to transmit through the generations. As I said at the outset, if I were choosing an egg to provide efficient energy processing for a future offspring, I’d pick someone sporty as the second mother — viz, someone unlike me. I spoke to scientists about this question — rather eminent ones — when I wrote about it previously, and they made clear that the nucleus isn’t a self-standing entity; it communicates with the rest of the ovum, with the mitochondria. It’s not like putting your nuclear genetic material into a nice clean empty space. In other words, as Professor Robert Winston pointed out bluntly, genetic modification is exactly what this technique involves.

But, given how squeamish we are about hurting anyone’s feelings, given our habitual utilitarianism, our willingness to put ends above means, what are the chances that MPs will call this technique what it is — a radical development in human genetic modification? Wouldn’t bet on it myself.

Tags: embryology, genetic modification, human genetics, Media, Morality, Parliament, Robert Winston, three parent babies