CRISPR-Cas9 genome editing can and has altered human genomes, bringing bioethical debates about this capability to the forefront of philosophical and policy considerations. Here, I consider the underexplored implications of CRISPR-Cas9 gene drives for heritable human genome editing. Modification gene drives applied to heritable human genome editing would introduce a novel form of involuntary eugenic practice that I term guerrilla eugenics. Once introduced into a genome, stealth genetic editing by a gene drive genetic element would occur each subsequent generation irrespective (...) of whether reproductive partners consent to it and irrespective of whether the genetic change confers any benefit. By overriding the ability to ‘opt in’ to genome editing, gene drives compromise the autonomy of carrier individuals and their reproductive partners to choose to use or avoid genome editing and impose additional burdens on those who hope to ‘opt out’ of further genome editing. High incidence of an initially rare gene drive in small human communities could occur within 200 years, with evolutionary fixation globally in a timeframe that is thousands of times sooner than achievable by non-drive germline editing. Following any introduction of heritable gene drives into human genomes, practices intended for surveillance or reversal also create fundamental ethical problems. Current policy guidelines do not comment explicitly on gene drives in humans. These considerations motivate an explicit moratorium as being warranted on gene drive development in heritable human genome editing. (shrink)