Charles Davenport, the leader of the eugenics movement in the United States in the early 20th century, defined eugenics as “the science of the improvement of the human race by better breeding” (1911:1). As such, eugenics implies the study of heredity, which is the passing of biological traits from one generation to the next, in order to limit the passing-on of undesirable traits through various methods of social influence and control. During the time that Davenport was writing, the study of heredity was well established in terms of its application to the section of certain traits in plants and domesticated animals, but the study of mechanisms of heredity was still in its infancy. Davenport believed that “The eugenical standpoint is that of the agriculturalist who, while recognizing the value of culture, believes that permanent advance is to be made only by securing the best “blood.” Man is an organism – an animal; and the laws of improvement of corn and of race horses hold true for him also” (1911:1). More specifically, Davenport (1911:4) described the relationship between heredity and eugenics as follows: “The general program of the eugenist is clear – it is to improve the race by inducing young people to make a more reasonable selection of marriage mates; to fall in love intelligently. It also includes the control by the state of the propagation of the mentally incompetent.”

Heredity as the central focus of eugenics
Despite the fact that Francis Galton (and later Karl Pearson) had been working on eugenic theories since 1883, heredity was still widely misunderstood at the turn of the 20th century. Prior to the development of modern genetic theories, it was commonly believed that physical traits seen in offspring resulted from the blending of parental characteristics. It was not until Gregor Mendel (1822–1884) addressed the question of heredity that the mechanisms involved in the inheritance of biological traits became understood. The results of Mendel’s now famous pea plant experiments (originally published in 1866, but not widely recognized until 1900) indicated that inherited traits are not the result of blending, but rather that different expressions of a trait are controlled by discrete units or particles – which we now understand to be genes – occurring in pairs in which one unit is inherited by the offspring from each parent.

The application of Mendelian theory to human beings would become a powerful analytical tool for eugenicists, particularly in the United States, who used pedigree analyses as the primary tool to study how Mendelian patterns of inheritance could be deduced in order to understand the heritability of physical, mental, and moral traits in humans, with the intention of improving the quality of the human population by selecting for desirable traits in the same ways that animal breeders sought to improve livestock. Davenport founded the Eugenics Record Office (ERO) in 1910, which was based at the Cold Spring Harbor Laboratory in New York. The ERO became a meeting place for eugenicists, a repository for eugenics records, a clearinghouse for eugenics information and propaganda, a platform from which popular eugenic campaigns could be launched, and a home for several eugenics publications.

The application of Mendelian genetics to human heredity and the establishment of the ERO would stimulate a large body of work in eugenics, focusing primarily on understanding what sorts of personality and social traits are inherited, what are their patterns of inheritance, and what are the best methods for maximizing the number of good traits and minimizing the number of bad traits within a population? Eugenicists believed that by carefully controlling human mating, conditions such as mental retardation, psychiatric illnesses, and physical disabilities could be eradicated. Among those presumably heritable characteristics that eugenicists sought to eliminate from the human population were “criminality,” epilepsy, bipolar disorder, alcoholism, and “feeblemindedness,” a term used to describe a variety of types of mental retardation and learning disabilities. In their studies of heredity of various traits, eugenicists often neglected to consider the possibility that environmental factors such as poor housing, poor nutrition, and inadequate education might influence the development of these traits. Nonetheless, since it was considered to be firmly rooted in the biological sciences, eugenics quickly became a public health issue that was advocated not only by scientists, but also by physicians and lawmakers. The unfortunate consequence being that the findings of these types of studies were used to justify policies aimed at removing certain genes from the population through such means as involuntary sterilization or institutionalization (i.e., negative eugenics). We now understand that most of the types of traits studied by eugenicists do not have a genetic basis.

-Michael Billinger

• Allen, Garland, 1986, “The Eugenics Record Office at Cold Spring Harbor, 1910-1940: An Essay in Institutional History.” Osiris 2(2): 225–264.

• Davenport, Charles Benedict, 1911, Heredity in Relation to Eugenics. New York: Henry Holt and Company.

• Lewis, Barry; Jurmain, Robert; Kilgore, Lynn, 2013, Understanding Humans: An Introduction to Physical Anthropology and Archaeology. Belmont, CA: Wadsworth, Cengage Learning.

• Norrgard, Kare, 2008, “Human testing, the eugenics movement, and IRBs.” Nature Education 1(1):170. Available at http://www.nature.com/scitable/topicpage/human-testing-the-eugenics-movement-and-irbs-724.