How did Gregor Mendel’s discoveries about heredity influence eugenicists?

Gregor Mendel’s discoveries regarding heredity, which were rediscovered in 1900, provided a crucial scientific framework for the eugenics movement. By demonstrating that physical traits were the result of discrete units—now known as genes—Mendel’s work offered eugenicists empirical evidence to support their belief that human characteristics were biologically determined and could be manipulated through selective breeding.21

Following this rediscovery, eugenicists increasingly formulated their theories in terms of genetics, viewing undesirable social and psychological conditions as the result of "defective" genes. This shift toward genetic determinism led to the categorization of individuals based on perceived hereditary fitness, which was used to justify discriminatory practices such as compulsory sterilization laws in the United States and Germany.21

It is essential to recognize that the application of Mendelian principles to complex human behaviors was scientifically flawed and ethically reprehensible. The misuse of these concepts to promote the marginalization or extermination of groups based on eugenic ideologies represents a profound violation of human dignity and fundamental ethical principles.13