Every December, Nature selects the 10 people of the year, those who have most shaped the year that is coming to an end. For 2025, the little KJ Muldoon, about whom we have written many times, could not be left out. The first newborn to receive a CRISPR treatment developed specifically for him, the inspiration for new rules on the testing of advanced therapies for rare diseases, the mascot that patients, families, doctors, and scientists needed to look to the future of medical editing with renewed confidence.