Genocide psychiatrist Robert Jay Lifton, the policy went through a number of iterations and modifications: {{quote|Of the five identifiable steps by which the Nazis carried out the principle of "life unworthy of life," coercive sterilization was the first. There followed the killing of "impaired" children in hospitals; and then the killing of "impaired" adults, mostly collected from mental hospitals, in centers especially equipped with carbon monoxide gas. This project was extended (in the same killing centers) to "impaired" inmates of concentration and extermination camps and, finally, to mass killings in the extermination camps themselves.}} See also Aktion T4'' Nazi concentration camp badges Holocaust victims Department of Film (Nazi Germany) Glossary of Nazi Germany: Useless eaters Nazi eugenics Nazism and race Sagamihara stabbings Social cleansing Am Spiegelgrund clinic References External links "Life Unworthy of Life" and other Medical Killing Programmes by Dr. Stuart D. Stein, University of the West of England Contemporary English translation of "Allowing the Destruction of Life Unworthy of life" by Dr. Cristina Modak German text online of Die Freigabe der Vernichtung Lebensunwerten Lebens The Holocaust in Germany Nazi eugenics Nazi terminology Holocaust terminology