Genetic editing has the potential to remove inherited diseases from the gene pool, but scientists and ethicists worry it could be used to create so-called "designer babies". This kind of work is now banned in many countries as the DNA changes can pass to future generations and possibly risks harming other genes.
The National Health Commission has said Prof He's work "violates China's laws, regulations and ethical standards" and has said that investigations have been initiated.
The case prompted a heated debate among the scientific community, with many raising concerns over the lack of verified data and the risks of exposing healthy embryos to gene editing.
"This is a truly unacceptable development", said Jennifer Doudna, a University of California-Berkeley scientist and one of the inventors of the CRISPR gene-editing tool that He said he used.
China has always been considered on the forefront of gene-editing technology, bankrolling expensive research projects and boasting less regulation in the field than Western nations. At 3-5 days a few cells were removed from the embryos to check for editing.
The researcher meant to delete both copies of the CCR5 gene, but one of the twins still has a single copy of the gene, so she will not have any extra protection against HIV. Those with one copy of the gene can still get infected with HIV, however some research suggests their health might decline more slowly if they do.
Although the science holds promise for helping people already born, the scientists said Thursday that it's irresponsible to try it on eggs, sperm or embryos because not enough is known yet about its risks or safety.More news: Amazon (AMZN) Launches New Service To Build And Manage Blockchains
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A medical team's quest to edit the genes of babies has been stopped by the Chinese government. It is not clear whether the participants fully understood objective and potential risks and benefits.
"Even if the modifications are verified, the procedure was irresponsible and failed to conform with worldwide norms", they said in a statement.
Many countries outlaw such experiments, and in the United States, using genetically altered human embryos for reproductive purposes is effectively banned by law. Staff at other hospitals were kept in the dark about the nature of his work to keep some of the participants information from being disclosed other than the fact that the samples might contain HIV.
But details of the experiment, which has not been independently verified, triggered an immediate backlash and He said the trial had been "paused".
The Southern University of Science and Technology in Shenzhen said earlier in the week he had been on unpaid leave since February, and it would be investigating the claims.
In China, where scientists have forged ahead with astonishing speed, regulations are still catching up.
"At this summit we heard an unexpected and deeply disturbing claim that human embryos had been edited and implanted, resulting in a pregnancy and the birth of twins", said the summit's organizing committee, which called for independent verification of He's claims that have so far not been published in a peer-reviewed journal. He did not file for clinical trial registry of his work until after it was completed and the twin girls were already born.