Georges-Louis Leclerc, Comte de Buffon (1707-1788) was the first to define "degeneration" as a theory of nature. Buffon incorrectly argued that entire species "degenerated" becoming sterile, weaker, or smaller due to harsh climates. By 1890 there was a growing fear of degeneration sweeping across Europe creating disorders that led to poverty, crime, alcoholism, moral perversion and political violence. Degeneration raised the possibility that Europe may be creating a class of degenerate people who may attack the social norms, this led to support for a strong state which polices degenerates out of existence with the assistance of scientific identification.
In the 1850s French doctor Bénédict Morel argued more vigorously that certain groups of people were degenerating, going backwards in terms of evolution so each generation became weaker and weaker. This was based on pre-Darwinian ideas of evolution, especially those of Jean-Baptiste Lamarck, who argued that acquired characteristics like drug abuse and sexual perversions, could be inherited. Genetic predispositions have been observed for alcoholism and criminality.
Max Nordau's 1890s bestseller Degeneration attempted to explain all modern art, music and literature by pointing out the degenerate characteristics of the artists involved. In this fashion a whole biological explanation for social problems was developed.
The first scientific criminologist Cesare Lombroso working in the 1880s believed he found evidence of degeneration by studying the corpses of criminals. After completing an autopsy on murderer Villela he found the indentation where the spine meets the neck to be a signal of degeneration and subsequent criminality. Lombroso was convinced he had found the key to degeneration that had concerned liberal circles.
In the twentieth century, eradicating "degeneration" became a justification for various eugenic programs, mostly in Europe and the United States. Eugenicists adopted the concept, using it to justify the sterilization of the supposedly unfit. The Nazis took up these eugenic efforts as well, including extermination, for those who would corrupt future generations. They also used the concept in art, banning "degenerate" (entartete) art and music: see degenerate art.