Skip to content
Home » News » After Three-Parent Babies, Will There Be ‘Multiplex Parenting’?

After Three-Parent Babies, Will There Be ‘Multiplex Parenting’?

By Michael Cook

Last week an all-star line-up of British researchers and administrators appeared before a committee of the House of Commons to tell MPs that the creation of three-parent babies was completely safe, ethical, and inconsequential.

The technique is known as mitochondrial transfer. Mitochondria swim in the soup surrounding the nucleus. Most of a cell’s DNA is in the nucleus, but about one percent resides in the mitochondria. If there is a defect in a woman’s mitochondria, her children may inherit serious defects.

Over the past couple of years a staple feature of British newspapers has been a teary profile of a couple whose child has a mitochondrial disease.

Take Vicky Holliday and her partner Keith Newell, for instance, who live in a large town on the outskirts of London. They spoke with The Guardian last week about their 10-month-old baby Jessica. She has Leigh’s syndrome, a condition probably caused by a flaw in the Vicky’s mitochondrial DNA. It results in lesions on the brain and Jessica will probably die in infancy.

There is no cure for Leigh’s syndrome, or other mitochondrial diseases, big or small. So the scientists are lobbying for permission to create embryos without the flawed mitochondrial DNA. The resulting children will have the nuclear DNA of the father and the mother and the mitochondrial DNA of another woman. In this way, Vicky and Keith would have a healthy baby to comfort them after the nearly inevitable death of Jessica. The media have christened such kids “three-parent babies.”

Over the past two years British scientists have dismissed ethical and medical misgivings about the procedure. But it’s not that simple.

Since the dawn of mankind, all of us have been the mingling of the DNA of one mother and one father. Our expectations of the rights and obligations of parents and children flow from this. We don’t know how people will feel about having a 100 percent daddy, a 99 percent mummy and a 1 percent mummy. Furthermore, this will be the first time scientists have ever changed the human germ line. The age of genetic engineering will have begun.

Even New Scientist magazine, which normally supports “progressive” science, did a 180-degree turn recently and called for “a serious debate about the ethics.” “We may have seriously underestimated the influence that mitochondria have,” it said in an editorial.

“Recent research suggests that they play a key role in some of the most important features of human life. This raises the ethically troubling prospect—once widely dismissed, including by this publication—that children conceived in this way will inherit vital traits from three parents.”

However, at this point, Britain’s science establishment appears to have bamboozled the politicians. It will probably get a green light to tinker with human embryos in the hope of creating disease-free children.


But what comes afterwards? Will three-parent embryos be the end of scientists’ interest? This is a question which leaps out of the pages of the November issue of the Journal of Medical Ethics, one of the world’s leading bioethics journals. MPs should read it—and shiver.

In it, one of Britain’s best-known bioethicists has enthusiastically shared his vision of children with four—or more—genetic parents. He calls it “multiplex parenting.” John Harris, of the University of Manchester, and two colleagues, César Palacios-González and Giuseppe Testa, contend that this is one of many tantalising consequences of using stem cells to create synthetic eggs and sperm. (Or as they prefer to call them, in vitro generated gametes [IVG].)

After the discovery of induced pluripotent stem cells in 2007, theoretically any cell in the body can be created from something as simple as a skin cell. Mice have already been born from sperm and eggs created from stem cells. Harris and his colleagues believe that the day is not far off when scientists will be able to do the same with humans. In their paper, they spin an ethical justification for this and outline some possible uses.

First, is it ethical? Of course it is, so long as experiments on mice show that it is safe. After all, they admit, this is already a much higher ethical bar than the one used for the first IVF babies. “If impractically high precautionary thresholds were decisive we would not have vaccines, nor IVF, nor any other advance. Nothing is entirely safe.” Besides, they argue, any children brought into the world are better off than if they never existed.

Second, there are many potential uses. The first four are familiar from the world of IVF: men who cannot produce viable sperm; women with premature menopause; people who have lost gonads or their fertility due to cancer treatment; and people who have been involuntarily sterilised (rare, but they do exist).

Many clients would be gay and lesbian couples who could have children who are genetically related to them both. “There is nothing morally wrong with same-sex competent caring people using IVG for satisfying their legitimate interests in becoming genetic parents of their children,” they say.

Another would be “single individuals, who may wish to reproduce without partner and without resorting to gamete donation.” This would be the most intense form of incest imaginable—an individual effectively mating with himself—so its safety is not guaranteed. But ethically, it gets a tick from Harris & Co.

Finally, “multiplex parenting,” an option which Harris and his colleagues tackle with great enthusiasm. This is “a radical expansion of reproductive autonomy that allowed more than two persons to engage simultaneously in genetic parenting.”

IVG could permit instead a much more substantive sharing of genetic kinship, through what is in essence a generational shortcut. Imagine that four people in a relationship want to parent a child while being all genetically related to her. IVG would enable the following scenario: first, two embryos would be generated from either couple through IVF with either naturally or in vitro generated gametes. hESC lines would be then established from both embryos and differentiated into IVG to be used in a second round of IVF. The resulting embryo would be genetically related to all four prospective parents, who would technically be the child’s genetic grandparents.


But why stop at four biological parents?

An Australian bioethicist, Rob Sparrow, of Monash University in Melbourne, has set his colleagues talking with an even more advanced scenario which he calls “in vitro eugenics.” By creating gametes from embryonic stem cells, it would be possible to create 20 or 30 generations of Petri dish humans in as little as 10 years.

It depends on how scientists manage the process, but over 20 generations you and I have acquired 1,048,576 ancestors. So four parents might be a conservative estimate. A child could have so many people contributing to their genetic makeup that there would be no meaningful connection to any parents. They would be, says Sparrow, “orphaned at conception.”

What is the purpose of this scenario? Eugenics: the elimination of unsatisfactory genes in the quest to create better human beings. “In effect,” Sparrow writes, “scientists will be able to breed human beings with the same (or greater) degree of sophistication with which we currently breed plants and animals.”


An ethical defence of possibilities like this is tall order. But Harris et al are up to it. In the first place, arguments drawn from what is “natural” are obviously irrelevant as there is no such thing as “natural” ways of acting. Hence, what can be wrong with opening up genetic kinship to a wider range of people than one father and one mother?

If there are some drawbacks, the child can hardly complain. It will exist, and existence is better than non-existence. In any case, even today, parenting involves many different individuals from different generations. The use of IVGs merely gives this reality a genetic component. “Prospective parents will be able to choose among a hitherto unimaginable variety of potential children,” they write.

Other contributors to the same issue of the Journal of Medical Ethics paint scenarios which are equally head-scratching. But the underlying theme of all the articles is that IVF technology can be used to completely reshape the landscape of parenthood. It’s the biological counterpart of deliberately inducing extreme climate change.

None of these developments is certain, of course. Even three-parent embryos may not succeed, let alone artificial eggs and sperm. But the latest issue of the Journal of Medical Ethics is clear evidence that some of Britain’s leading academics have already drawn a roadmap for creating children who are the playthings of curious geneticists. It would be utterly irresponsible of the British Parliament to legalise three-parent embryos without examining what the next act will be.

Michael Cook is editor of MercatorNet. 

This article has been reprinted with permission and can be found at