Asperger at first warned against classifying children, writing in 1937 that “it is impossible to establish a rigid set of criteria for a diagnosis.” But right after the Nazi annexation of Austria in 1938 — and the purge of his Jewish and liberal associates from the University of Vienna — Asperger introduced his own diagnosis of social detachment: “autistic psychopathy.”

As Asperger sought promotion to associate professor, his writings about the diagnosis grew harsher. He stressed the “cruelty” and “sadistic traits” of the children he studied, itemizing their “autistic acts of malice.” He also called autistic psychopaths “intelligent automata.”

Some laud Asperger’s language about the “special abilities” of children on the “most favorable” end of his autistic “range,” speculating that he applied his diagnosis to protect them from Nazi eugenics — a kind of psychiatric Schindler’s list. But this was in keeping with the selective benevolence of Nazi psychiatry; Asperger also warned that “less favorable cases” would “roam the streets” as adults, “grotesque and dilapidated.”

Words such as these could be a death sentence in the Third Reich. And in fact, dozens of children whom Asperger evaluated were killed.

Child “euthanasia” was the Reich’s first program of mass extermination, begun by Hitler in July 1939 to get rid of children regarded as a drain on the state and a danger to its gene pool. Most of the victims were physically healthy, neither suffering nor terminally ill. They were simply deemed to have physical, mental or behavioral defects.

At least 5,000 children perished in around 37 “special wards.” Am Spiegelgrund, in Vienna, was one of the deadliest. Killings were done in the youths’ own beds, as nurses issued overdoses of sedatives until the children grew ill and died, usually of pneumonia.

Asperger worked closely with the top figures in Vienna’s euthanasia program, including Erwin Jekelius, the director of Am Spiegelgrund, who was engaged to Hitler’s sister. My archival research, along with that of other scholars of euthanasia like Herwig Czech, the author of a forthcoming paper on this subject in the journal Molecular Autism, show that Asperger recommended the transfer of children to Spiegelgrund. Dozens of them were killed there.