Eugenics is the science of improving the human species by selectively mating people with specific desirable hereditary traits.
It aims to reduce human suffering by “breeding out” disease, disabilities and so-called undesirable characteristics from the human population.
Eugenics encouraged people of so-called healthy, superior stock to reproduce and discouraged reproduction of the mentally challenged or anyone who fell outside the social norm.
Modern eugenics, more often called human genetic engineering, has come a long way scientifically and ethically and offers hope for treating many devastating genetic illnesses. Even so, it remains controversial.
While eugenic principles have been practiced as early as ancient Greece, the contemporary history of eugenics began in the early 20th century, when a popular eugenics movement emerged in the United Kingdom,
A major criticism of eugenics policies is that, regardless of whether negative or positive policies are used, they are susceptible to abuse because the genetic selection criteria are determined by whichever group has political power at the time.
Negative eugenics in particular is criticized by many as a violation of basic human rights, which include the right to reproduce.
Another criticism is that eugenics policies eventually lead to a loss of genetic diversity, thereby resulting in inbreeding depression due to a loss of genetic variation.
Another criticism of contemporary eugenics policies is that they propose to permanently and artificially disrupt millions of years of evolution, and that attempting to create genetic lines "clean" of "disorders" can have far-reaching ancillary downstream effects in the genetic ecology, including negative effects on immunity and species resilience.