Part of the reason he went ahead, He said, was his observation of earlier public survey and study results in the United States and the United Kingdom indicating a majority in society seemed to find the idea acceptable.

Lovell-Badge said He failed to do research in a properly controlled and careful manner, including publishing findings along the way and involving authorities in making decisions whether to go further.

The process of obtaining patients' informed consent was poorly executed, Lovell-Badge said.

Wei Wensheng, a professor at Peking University, asked He why he chose to cross a red line by performing clinical trials in secret.

That red line－the international consensus on prohibiting genome editing on germlines, which can pass on their genetic material to offspring－has been observed by the Chinese science community since the first human genome editing summit in 2015.

In response, He said he had consulted several institutions for feedback.

Many technical questions were raised about the necessity and authenticity of He's experiment.