Last month, an international commission convened to consider whether and how germline editing – changing the genes passed on to children and future generations -- should proceed. The discussions focused mainly on the safety risks of the technology, which, while important, are not the only issues to consider. Any conversation regarding germline editing must also honestly and thoroughly assess the potential benefits of the technology, which, for several reasons, are more limited than generally acknowledged.

The birth of gene-edited twin girls was announced by a young Chinese scientist He Jiankui through one of four self-made promotional videos in English on YouTube (a website officially banned in China) on November 25. Three days later, at the Second International Summit on Human Genome Editing held in ...