World's first 'three-parent' baby born

Three-parent babies: medical miracles or 'designer' infants?

23 July 2014

The government has approved a treatment that would allow babies to inherit genetic material from three parents.

The first "three-parent babies" could be born next year, the Daily Telegraph reports, with MPs likely to vote on legalising of mitochondrial replacement therapy after a three-month consultation period.

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The technique, which seeks to correct genetic defects before a child is even conceived, has inspired passionate debate within the worldwide scientific community. But how does the treatment work, and why might some be opposed to its implementation?

How do scientists create a three-parent baby?

Mitochondrial replacement therapy involves the removal of defective DNA from a mother's genetic pool and its replacement with healthy material from a third-party donor.

Doctors start by taking out "the nucleus from a donor egg and replac[ing] it with genetic material from the mother's egg", says the Telegraph. Afterwards, the egg is fertilised using the father's sperm and can be implanted into the mother using in-vitro techniques.

Why would a baby need another set of mitochondrial DNA?

Mitochondria "are tiny powerhouses in cells that generate energy and have a small amount of their own DNA, separate from the bulk of the human genetic code", says the Belfast Telegraph.

Defects in mitochondrial DNA, which are inherited from the mother's side, can have serious effects upon a child's health. According to The Independent, mitochondrial flaws "can cause muscle wasting, heart problems, vision loss, organ failure, and epilepsy".

The Times says that "about 100 children every year suffer life-threatening problems" as a result of their genetic heritage.

Children who have received the treatment will pass on healthy DNA, The Independent says, so genetic diseases will not resurface in future generations.

Can the third set of DNA affect the personality or appearance of a child?

The Times says that "less than one per cent of a child's genetic material would come from the donor and it would not affect traits such as appearance or intelligence".

How will the process be regulated?

The Department of Health has proposed stringent measures to regulate the use of mitochondrial replacement therapy. Applications will be decided on "a case-by-case basis" and candidates must demonstrate "that there is a risk of 'mitochondrial abnormality' and a significant risk that a person would be born with, or develop a serious physical or mental disability without the treatment," the Telegraph says. The paper estimates that regulations would allow "about 80 women a year" to receive therapy.

The government also promises to protect the identities of anonymous DNA contributors. According to the proposed guidelines, "a baby born through the process cannot find out who their 'second mother' was, although non-identifying information can be given after the age of 16".

How has the public reacted to the proposal?

Proponents of mitochondrial replacement therapy have praised the government's decision to recommend the treatment and called for parliament to approve it quickly.

"Many couples would like to have a healthy child soon," said Professor Frances Flinter of King's College, London. "They will be anxious about any further delays in bringing legislation before parliament."

However, "critics argue that the treatment could be the first step towards 'designer babies' and even eugenics", says The Independent. Activist groups such as Human Genetics Alert believe the treatment "is unethical and the benefits cannot justify the unknown risks to the child", says the Telegraph.

"Looking back, 15 years from now in the midst of a eugenic designer baby marketplace, people will see this as the moment when the crucial ethical line was crossed," says HGA head Dr David King. "Britain will now be isolated in Europe as the only country permitting human genetic manipulation".

In response, The Department of Health insisted that mitochondrial replacement therapy does not amount to the creation of genetically modified humans.

"There is no universally agreed definition of 'genetic modification' in humans," it said. "People who have organ transplants, blood donations or even gene therapy are not generally regarded as being 'genetically modified'."