The Thin Red Line

When Chinese researcher He Jiankui revealed that he had edited the embryos of twin girls to protect them from HIV, it triggered an international uproar. Critics said he had crossed a red line. Now Denis Rebrikov, a geneticist in Moscow, wants to edit embryos of a deaf couple to prevent them from passing on the mutation that compromised their hearing. Unlike He, Rebrikov is open about his plans, seeking high-level regulatory approval, and addressing the critics head on. Pulitzer Center grantee Jon Cohen traveled to Russia to meet with Rebrikov, the couple, bioethicists, geneticists, and Ministry of Health officials.