In 1870 British psychologist Herbert Spencer began to widely promote eugenics and claimed that selective breeding of the fittest would bring about a superior race and the unfit should be allowed to die out. He recommended that natural selection be allowed to take it's course and stated that the government should do nothing to help the poor, weak or "unfit". Herbert Spencer also claimed that aiding the children of the poor was a serious crime against society because it would "disadvantage the offspring of the worthy." He named his brand of eugenics "evolutionary psychology." He opposed enacting laws to mandate safety standards for housing, clean-water systems, effective sewage systems and mine and factory regulations because they represented an "artificial preservation of those least able to take care of themselves."
The United States was not immune to the eugenics ideology. In 1896, Connecticut enacted a law prohibiting the "insane" from marrying. Other states followed, threatening the mentally ill with a $1000 fine and five years in prison if they wed. Charles Davenport, who studied British psychological eugenics, argued that if a society had to choose between allowing "mental defectives" to procreate or executing them, the latter was preferable.
By the 1920s, eugenic sterilization was practiced in two dozen states. In 1921, the Second International Congress on Eugenics in New York declared that science should "enlighten government in the prevention of the spread and multiplication of worthless members of society."
During the 1930s, United States immigration policies were guided by eugenics theories, and many peoples of Italian and Easter European descent were turned away. And, to a large extent, as in Germany, anti-Semitism was fueled by advocates of the eugenics fallacy.
As last as 1974, women on welfare were twice as likely as other women to be sterilized. 25% of Native American woman had been sterilized and a decline in fertility was most pronounced amount African and Mexican Americans.
These same theories of eugenics inspired Adolf Hitler in his seminal book "Mein Kampf" (My Struggle).