Long before ChatGPT infiltrated classrooms and became an obsession at cocktail parties, Boston Children’s Hospital embarked on what Dr. John Brownstein, its chief innovation officer, described as an “A.I. journey.” For years, Brownstein told me, the hospital had been using machine learning in data-rich environments—like radiology, pathology, or the intensive care unit—to generate “predictions” about patient outcomes. Then came the generative A.I. explosion. Now, Brownstein said, his team is anticipating that A.I. is “going to be part of the fabric of almost all the technologies we use in the hospital.” For many people in the A.I. field, the integration with medicine represents a potential holy grail.