BEIJING/SHANGHAI (Reuters) – Chinese officials and scientists denounced on Tuesday the claims of a geneticist who said he had created the first gene-edited babies, and a hospital linked to his research suggested its ethical approval had been forged.

More than 100 scientists said in an open letter the use of CRISPR-Cas9 technology to edit the genes of human embryos was risky, unjustified and harmed the reputation and development of the biomedical community in China.

In videos posted online, scientist He Jiankui defended what he said he had achieved – embryonic gene editing to help protect twin baby girls born this month from infection with HIV, the virus that causes AIDS.

“Pandora’s box has been opened. We still might have a glimmer of hope to close it before it’s too late,” the scientists said in their letter, a copy of which was posted by the Chinese news website the Paper.

“The biomedical ethics review for this so-called research exists in name only. Conducting direct human experiments can only be described as crazy,” the approximately 120 scientists said in the Chinese-language letter.

Yang Zhengang, a Fudan University professor, told Reuters he signed the letter because gene editing was “very dangerous”.

China’s Genetics Society and the Chinese Society for Stem Cell Research said in a statement He had acted as an “individual” and his work posed “tremendous safety risks for the research subjects”.

“We believe the research led by He is strongly against both the Chinese regulations and the consensus reached by the international science community,” the two groups said in a statement posted online.

CRISPR-Cas9 is a technology that allows scientists to essentially cut-and-paste DNA, raising hope of genetic fixes for disease. However, there are also concerns about its safety and ethics.

(Graphic explaining the Crispr DNA editing technique, tmsnrt.rs/2ReKG1R)

He, who is due to speak at a summit on human genome editing at the University of Hong Kong on Wednesday, did not respond to a Reuters request for comment.

The Shenzhen Harmonicare Hospital, listed on China’s online clinical trial registry as having given ethical approval for He’s experiment, denied having ever taken part in any clinical operations relating to “gene-edited babies”.

The signatures on the online form were suspected of having been forged and “no relevant meeting of the Medical Ethics Committee of the hospital in fact took place”, Hong Kong-listed Harmonicare Medical Holdings said in a statement.

‘VERY SHOCKED’

The Southern University of Science and Technology, where He holds an associate professorship, also said it had been unaware of the research project and that He had been on leave without pay since February.

The Shenzhen City Science and Innovation Committee, a municipal fund which was also listed on the clinical trial registry as having backed the trial, said in a statement on Monday it had never been involved in the project.

Xu Nanping, vice minister of China’s science and technology ministry, told reporters he was “very shocked” on hearing He’s claim, adding that such work had been prohibited since 2003.

Details of the case were still unclear, Xu said.

“We don’t know if this work is real or fake. If it’s real, then this is certainly banned in China.”

The official Xinhua news agency said ethics could not be ignored.

“Scientific exploration is never-ending … but this does not mean that the morals of science can be abandoned or that ethical standards can be ignored,” the news agency said in a comment posted on social media.

The National Health Commission said on Monday it was “highly concerned” and had ordered provincial health officials “to immediately investigate and clarify the matter”.

The government’s medical ethics committee in Shenzhen said it was investigating the case, as was the Guangdong provincial health commission, according to Southern Metropolis Daily, a state media outlet.

The committee organizing the Hong Kong conference where He is due to speak – the Second International Summit on Human Genome Editing – said in a statement on Monday it had only just been informed of He’s work on the genes of the twin girls.

“Our goal is to help ensure that human genome editing research be pursued responsibly,” the committee said.