Embryo editing technique is ‘ethically dubious’, fertility expert warns

An embryo editing ‘breakthrough’ is ethically dubious and could have irreversible results if given legal approval, a leading fertility expert has warned.

Professor Lord Robert Winston was responding to the news that scientists from the US, China and South Korea successfully removed DNA which causes a heart defect from human embryos for the first time.

But critics are concerned that the technique involved could one day be used to create “designer babies”, where certain characteristics of an unborn child – such as its skin colour, height or weight – are modified to the specifications of its parents.


Using a tool known as Crispr-Cas9, researchers altered DNA which causes hypertrophic cardiomyopathy in 58 embryos and allowed them to develop for a further five days.

At the end of the controversial experiment, one in four embryos had redeveloped the problem DNA. All of the embryos were subsequently destroyed.

In a letter to The Times, Professor Winston warned: “If we do go down the route of genetic modification using Crispr-Cas9 or any other similar technology, unpredictable mistakes would be inevitable and the results irreversible.”

Lord Winston is an Emeritus Professor of Fertility Studies at Imperial College London and believes the ethical justification for the technique “seems highly dubious given that neither the embryo nor any subsequent generation could give informed consent”.

‘Playing God’

Scientists from Stanford University have also warned that the embryo editing technique could be seen as ‘playing God’ in an attempt to create the ‘best children’ possible.

The scientists said: “At this time, given the nature and number of unanswered scientific, ethical, and policy questions, it is inappropriate to perform germline gene editing that culminates in human pregnancy.”

Although critical of Crispr-Cas9, Lord Winston does support pre-implantation genetic diagnosis, a controversial embryo screening technique which has been likened to eugenics.

And despite initially speaking out against techniques for three and four parent babies, sometimes known as ‘mitochondrial replacement’, he subsequently performed a U-turn after coming under pressure to alter his stance.


It is currently illegal for scientists in the UK and the US to modify an embryo using Crispr-Cas9 and implant it in the womb.

However, the UK Government does allow controversial three or four-parent baby techniques.

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