The term eugenics, meaning "wellborn," was coined in 1883 by Francis Galton, the scion of an upper-class British family and a cousin of Charles Darwin. Galton wrote that he intended it as "a brief word to express the science of improving the stock, which...takes cognizance of all the influences that tend...to give the more suitable races or strains of blood a better chance of prevailing speedily over the less suitable than they otherwise would have had." Included among the "less suitable" strains of blood were "paupers," "drunkards," and the "feebleminded," loosely defined. So, race and class prejudices were there from the start.
Genetics did not yet exist as a science, though the Czech monk Gregor Mendel published his classic paper in 1865. Mendel's laws of inheritance only became widely known after the paper was rediscovered in 1900. Not long after that, geneticists began to examine patterns of inheritance of human traits such as hair or eye color and of diseases. By constructing family pedigrees, they showed that similar regularities exist in the way human...