Having worked in various psychiatric hospitals most of my adult life I can assure people that the practice of admitting girls who got pregnant under the pretence of being mentally retarded ceased in the 1930s. The Mental Health Act of 1959 imposed very strict controls on who could be admitted and detained in mental hospitals. Many of the sections required two medical recommendations as well as an application from an appropriately qualified social worker. Also the difference between being "mentally handicapped" and "mentally ill" is very great. The position in Nazi Germany regarding the "final solution" was a bureaucratic one probably instigated by Hitler who was careful to ensure that little or no evidence remained to implicate him.