Sir Francis Galton coined the term "eugenics" in 1883, referring to selective breeding among humans to improve traits like intelligence that he believed were inherited. There were efforts to promote positive eugenics through encouraging reproduction among those deemed "fit" and negative eugenics by discouraging or preventing reproduction among those deemed "unfit." The U.S. enacted sterilization laws and restricted immigration in the early 20th century based on eugenicist ideas about improving the genetic stock of the population.