Eugenics (also known as Selective Breeding) the philosophy or practice of selectively breeding traits in or out of a group of organisms. While widely used in botany and horticulture, eugenics via genetic engineering in sentient lifeforms is illegal in the Federation.
Kodos used his own personal theory of eugenics when killing 4000 people on Tarsus IV. (TOS: "The Conscience of the King")