London - British scientists have condemned a "monstrous" experiment that is said to have created the world’s first genetically edited babies in China.
Dr He Jiankui said he made twins incapable of being infected by HIV by disabling the CCR5 gene that allows the deadly virus to get into human cells.
He claims to have done this in two girls, named Nana and Lulu, who were born in China a few weeks ago, although the research has not been published or independently verified.
Doing this in living babies is illegal in many countries, including the UK, where scientists and ethicists accused the researcher of "highly irresponsible, unethical and dangerous" science, akin to "genetic Russian roulette".
People without the CCR5 gene may be protected from HIV but are at greater risk from other viruses, including hepatitis B and West Nile virus, as well as dying of flu.
Experts say gene editing also puts babies in greater danger of severe birth defects and cancer.
Dr He, from Southern University of Science and Technology in Shenzhen, recruited HIV-positive men and their partners for fertility treatment, offering to protect their children from the virus. The chances of a father passing on HIV are close to zero when the mother is not infected.
Couples were given fertility treatment, with the gene-editing CRISPR-Cas9 protein injected into the mother’s egg with the sperm. This acts like molecular scissors to ‘snip out’ the CCR5 gene that triggers a protein to allow HIV into cells.
Dr He said 16 out of 22 embryos were edited, and 11 were used in six IVF attempts before a woman became pregnant with her twins.
Dr He’s experiment, revealed before an international gene editing conference in Hong Kong, was described as "monstrous" by Professor Julian Savulescu, director of the Oxford Uehiro Centre for Practical Ethics at the University of Oxford.
He said: "It contravenes decades of ethical consensus and guidelines on the protection of human participants in research. In many other places in the world this would be illegal, punishable by imprisonment.
"These healthy babies are being used as genetic guinea pigs. This is genetic Russian roulette."
Dr Dusko Ilic, from the faculty of life sciences and medicine at King’s College London, said: "These people should face criminal trial – they were experimenting with children’s lives with no reason for doing it.
"Gene editing technology is not perfect and… can cause birth defects, from spina bifida to learning disabilities, and could create genetic diseases we have never even heard of before."
The fear over gene editing is that the CRISPR-Cas9, made up of a homing molecule and a "scissor" protein to cut DNA, can zero in on the wrong part, raising the risk of other illnesses by introducing genetic mutations.
However, Dr He’s team claimed cells removed from the resulting embryos, and the babies when they were born, show the gene editing worked safely.