Eugenics was one of the darkest movements of the Progressive era. The eugenics movement argued that preserving "superior" humans will create a more productive and healthy class of people. It dated back to Francis Galton's idea that encouraging procreation among the supposedly superior would create a fitter group of people and preserve the white race, who eugenicists considered innately superior. American eugenicists persuaded people that certain characteristics such as race and disability were degenerate. In reality, they simply sought refuge in the idea of improving white Americans to justify maintaining power over people of color and the disabled. In fact, this movement led to restrictions on interracial marriage and lifelong sterilization of innocent people. Eugenics perpetuated discrimination under the veil that eugenics would create a better society, however, the underlying goal was to exercise social control and power over African Americans and disabled people.