Control Eugenics

In 1883, Francis Galton, a cousin of Charles Darwin, coined the word "eugenics" to express his dream of perfecting the human race by applying the laws of genetic heredity. Adapting Darwin's theory of evolution to human society, eugenics soon became a powerful, international movement, committed to using the principles of heredity and statistics to encourage healthy and discourage unhealthy reproduction. Early in the twentieth century and across the world, doctors, social reformers, and politicians turned to the new science of eugenics as a means to improve and strengthen their populations. Eugenics advocates claimed their methods would result in healthier, fitter babies and would dramatically limit human suffering.

How did an obscure academic idea pave the way to the Holocaust within just fifty years?