Top scientists and ethicists from seven countries have called for a global moratorium on gene editing of human eggs, sperm or embryos that would result in genetically altered babies after a Chinese researcher last year announced the birth of the world’s first gene-edited twins.

News of their birth prompted global condemnation of the work, raising the ethical spectre of so-called designer babies, in which embryos could be genetically modified to produce children with desirable traits.

The scientists and ethicists want to halt genetic alterations of germline cells that can then be inherited by others and “could have permanent and possibly harmful effects on the species”.

“The governance framework we are calling for will place major speed bumps in front of the most adventurous plans to re-engineer the human species,” they wrote.