Birth of a new era: Three parent baby - positive step or genetic minefield?
A controversial procedure has enabled previously infertile parents to give birth. Are we entering the age of the three-parent baby
The doctor who helped to pioneer the procedure has hailed it as the "opening of a new era" for couples struggling to conceive a baby.
An egg containing the genetic material from three parents has been used for the first time to allow an infertile couple to have a baby. Previously, the technique has only been used to prevent genetically transmitted diseases.
The successful birth, announced earlier this month by Dr Valery Zikin and a team in Ukraine, potentially offers hope for thousands of Irish couples who are having difficulties in producing viable embryos.
But it also raises a whole panoply of questions about the parenthood of the baby, and whether children born using the technique could carry genetic defects. Other fertility experts, including those carrying out IVF in Ireland, are sceptical.
As well as a biological mother and father, the baby girl carries a small amount of genetic material from a second woman.
Could we see "three-parent" babies here as Irish clinics move to copy the technique? And would the resulting children have the right to trace the identity of the donor?
While this procedure has recently been approved for infertile couples in the UK, there is no law governing the technique here.
Legislators in Ireland have struggled to keep pace with developments in IVF. New laws which permit the child produced from a donor sperm or a donor egg to trace their biological parent have been enacted, but have not yet come into force.
Professor Simon Fishel, who was part of the team that produced the world's first IVF "test tube" baby in 1978, tells the Irish Independent: "In theory the procedure (that produced the baby in Ukraine) could be done in Ireland, but I don't think any responsible practitioner would do it at the moment."
Dr Lynne O'Shea, a leading fertility researcher at UCD, agrees.
She says: "It's a very interesting technique and has a lot of merit scientifically from work that has been done on animals.
"But it is still highly experimental and until it is subjected to the full scientific trials, we don't know the potential dangers. It is the unknown element that is the worrying factor at the moment."
The girl is thought to be the world's second "three-parent baby" after another child was created using a slightly different technique in Mexico last year.
The Kiev team fertilised the mother's egg with her partner's sperm and then transferred the combined genes into an egg taken from a donor. The child has the genetic identity of its parents, combined with small amounts of DNA from the second woman.
While this latest "three-parent" birth was the first designed to remedy infertility, the method employed last year in Mexico was intended as a way of preventing inherited genetic disease.
The genetic material which causes these disorders is mainly found in a cell's mitochondria, while the nucleus contains the genes that pass on a baby's main characteristics and appearance. It is hoped that by transplanting the nucleus into healthy mitochondria of a third person, parents can avoid passing on disease to their offspring.
Professor Fishel, who is director of Beacon Care Fertility in Dublin, says: "If the technique is being used for mitochondrial disease, there is very good evidence that this will help families.
"It will mean future children are at far lower risk of transferring the disease of their parents to their own children. That is good positive medicine."
However, he adds: "If one is doing it for the improvement of egg quality for general infertility treatment purposes, there is no good evidence that it would even work."
Despite sharing some of these reservations, Dr John Kennedy, medical director of Sims IVF Clinic in Dublin, predicts that in the long term a procedure such as this is likely to be available in Ireland to treat infertility.
"Couples have a very strong desire to have families and they don't want to have to wait. If there is evidence from other reputable countries that they are doing it successfully, there will be enormous pressure on us to follow suit.
"There are pros and cons to it. As human beings we are only supposed to have the genetic material from two people. These people will have three genetic codes.
"Theoretically they all may look fine and healthy, but we don't know what the impact will be down the line."
So how many characteristics would the baby inherit from their parents - and how much from the donor? Almost all of the DNA will come from the mother and father. That's because most of our genes are found in the cell's nucleus; and a small number are found in the mitochondria. Dr O'Shea says the child would inherit less than 1pc of the donor's genes. Professor Fishel likens the genetic make-up of these "three-parent" babies to a car.
"It would be like putting a BMW battery in a Rolls Royce. You would still call the car a Rolls Royce."
Under new laws, which are set to be implemented shortly, children will be able to trace the identity of egg or sperm donors once they reach the age of 18.
But when the legislation was drawn up, it did not take into account the use of mitochondrial tissue in an egg from a third party.
UCC law Professor Deirdre Madden, an authority in this area, says in Britain, children born using this technique in the future will not be entitled to trace the identity of the donor. "It is hard for legislators to keep up with the developments, because science moves at a much quicker pace than the law," she says.
The Kiev technique has been dubbed "pronuclear transfer" and was administered after the couple underwent four failed cycles of IVF. Dr Zikin, head of the team at the Nadiya clinic in Kiev, has said the treatment could assist women whose embryos stop growing before they can be implanted in a womb. This affects around one in 150 IVF patients, but the doctors hope to broaden its use.
Dr Zikin said: "Before, we could only increase the selection of embryos, but for us this moment opens up the possibility of augmenting embryos." The clinic is also trying to use the method to revitalise the eggs of women in their 40s.