Increasingly, are reaching for A.I. chatbots to explain new symptoms, weigh treatment options and vet their doctors' conclusions. About one in six adults — and about a quarter of adults younger than 30 — use chatbots to find medical advice and information at least once a month, according to a recent survey from KFF, a nonprofit health policy research organization. Supporters hope A.I. will empower patients by giving them more comprehensive medical explanations than a simple Google search might.