Leading scientists are calling for a global moratorium on editing human genes that can be passed down generations, after the Chinese scientist He Jiankui outraged the international research community by claiming he had edited the genes of twin babies.

Experts including scientists who worked on the development of the Crispr technique for genome editing and the US National Institutes of Health said they wanted a temporary ban on the clinical use of the techniques for editing eggs, sperm or embryos. Editing genes to cure diseases in patients, but not their offspring, would still be permitted, as would research.

In an opinion piece in the journal Nature, 18 specialists from seven different countries said the ethical, societal and moral issues should be discussed and nations should establish an international framework on the conditions in which such editing could be allowed.