"Have you read Malthus?"

Thomas Malthus
Public DomainThomas Malthus
Essays on the Principles of Population (published  1798, 1803, 1806, 1807, 1817 and 1826), by Thomas Malthus (1766-1834), argued that overpopulation was the greatest threat to the continuing improvement of society. As well as identifying pre-existing controls on population, such as disease, war and contraception, he suggested that the remaining threat of overpopulation could be avoided through "moral restraint": late marriage and celibacy.

When Malthus discusses the theory of human eugenics, he rejects the idea because it would require the consignment of all the "bad specimens" to celibacy.