Nathaniel Comfort in The Point:
The notion that your genes are your essential self—genetic essentialism—is fairly recent. Although the idea that heredity contributes to our health and identity is ancient, the idea that for practical purposes it is all that matters dates only to the nineteenth century. The English statistician Francis Galton conceived of heredity as a subterranean stream of “germ plasm,” flowing down the generations, isolated and insulated from the environment’s buffeting of any individual body. In determining who we are, Galton wrote, nature was “far more important than nurture.”
That stream was increasingly polluted, Galton was convinced. Vexed by the fact that people paid more attention to breeding their cattle than themselves, in 1883 he proposed a scheme of hereditary improvement he called “eugenics,” meaning “well-born.” The stream of British germ plasm could be socially filtered, and even enriched, by persuading the “fittest” people (borrowing loosely from Darwin) to have more children; the “unfit,” fewer. A techno-optimist to the core, Galton believed that, given proper instruction, people would see the logic of this scheme and participate voluntarily. In this he was naïve—at least about the abstinence part. After 1900, eugenics became coercive, while the state’s trust in the population shriveled. Marriage restriction and sexual sterilization laws were keystones of state-run programs of hereditary improvement. When most people think of eugenics, they think of a scientifically rationalized program of racial purification, which it was. But eugenics always had a medical and public health dimension as well. The vast majority of forced sterilizations were carried out in a medical milieu—particularly in psychiatric hospitals. Eugenic sterilization was considered preventive medicine for incurable mental or other hereditary disease. This is the origin of medical genetics. Mainstream genetic medicine today isn’t eugenics, but it has a deep taproot in ideas of hereditary social control.