Andrew Fergusson reports

Andrew Fergusson

We're all aware of three parent families - relationships have ended and new ones begun, so sometimes there are three or more parents involved in any one family group. But this April, we began to hear about 'three parent embryos'. What's it all about?

To understand the complex medical technology involved, so we can then assess the ethical issues, we need to consider developments in medical technology and reproduction. In the early 1960s the oral contraceptive pill gave us sex without babies. Following the birth of the world's first test tube baby, Louise Brown in 1978, IVF technology has given us babies without sex. Skills learned have led to the potential for remarkable genetic treatments for more and more conditions. The latest 'breakthrough' announced in April was a potential treatment for mitochondrial diseases. What on earth are they?

Mitochondria are the little energy packages within almost all cells in the body. When a sperm fertilises an egg and an embryo is formed, with all its potential to lead nine months later to the birth of a baby, almost all of the genetic material passed on from the two parents is found in the genes in the 46 chromosomes of the embryo's nucleus. But some genes are also transmitted via these mitochondria, and occasionally defective genes cause diseases. Around one in 200 children is born each year with mutations in mitochondrial genetic material, and while in most cases this causes only mild disease, sometimes without symptoms, around one in 6,500 children is born with serious mitochondrial disease which can include conditions like heart failure and muscular weakness.

Scientists in Newcastle have developed a technique which would potentially allow them to replace defective mitochondria during IVF. In embryos left over from IVF treatment, the nuclei, containing genetic material from both parents, were removed and the faulty mitochondria left behind. Each nucleus was then put into another egg which had been hollowed out so that it was minus its own nucleus but with its own - healthy - mitochondria.

One of the experimenters said: 'What we've done is like changing the battery on a laptop. The energy supply now works properly, but none of the information on the hard drive has been changed. A child born using this method would have correctly functioning mitochondria, but in every other respect would get all their genetic information from their father and mother.'

So, if that was entirely true, and if this technology was allowed, and if it worked, those two parents could have a healthy baby who would not develop the mitochondrial disease. Isn't that a good thing? What could possibly be wrong? There are big issues. First, the law currently prevents the technique being used in fertility treatment, and a licence to carry out this very research was refused on two occasions before being granted five years ago. However, in the light of these early research results, it is not unlikely that the regulatory changes (which now no longer involve Parliament but only approval from the health minister) would be approved.

Why is current law so cautious? Surely granting parents-to-be healthy babies is a good thing? Well, medicine rightly follows the rule 'first do no harm' and there are concerns about safety issues should this early research become a treatment:

• As the embryos developed and babies were born what might be the effect of the small amount of defective mitochondrial material still being transferred?


• Would the babies born be normal or suffer from defects worse than the original mitochondrial disease? (We know from comparable research in related areas that normal development fails quite early on.)

But there are also important ethical questions which must be asked and answered:

• What about the hundreds of embryos already destroyed in the research? Is a human embryo merely a potential human being, with no absolute value in God's eyes or, rather, a human being with potential, made in the image of God and worthy of protection?


• Will concentrating on glamorous high-tech research lead to patients who already have mitochondrial diseases being neglected in treatment?


• What might be the effect of the transmissible genetic material on future generations? Forgetting for a moment the unproved safety issues, to license this approach would be the first legalised example of so-called germline therapy - treatment that does not just affect one individual but the lives of all down the generations who might follow.


• What might be the psychological effect on the baby, who becomes a child, who becomes an adolescent with all the usual 'identity' issues, who becomes an adult? What might the effect be when their genetic material comes from three parents?

It's a crude way to finish this brief summary of complex scientific and ethical questions, but who gets the Mother's Day card?