Since its origins, Homo sapiens has driven many species to the brink of extinction—and sometimes irreversibly beyond it. We have done so to feed, defend, colonize, cultivate, and enrich ourselves—often without fully realizing it. To do so today, deliberately, in an era of biodiversity treaties and conservation efforts, might seem absurd or extreme. Yet there is no shortage of organisms deemed highly harmful to human health or the environment. Under what conditions might it be justifiable to eliminate them using genetic technologies? Do we have the right to erase another life form from the face of the Earth?