[1] As a practitioner of medicine, he worked in the university psychiatric clinic, later as a scientific assistant at the Max Planck Institute of Psychiatry in Munich and until 1934 as a doctor in the medical centre of Branitz, near Oppeln, in Upper Silesia.
Starting on 1 March 1939, Rodenberg worked as a criminal biologist in the department for the care of race and heredity in the Reichsgesundheitsamt (Reich Office for Health).
[2] In this capacity he decided on the basis of questionnaires with the data of the sick and disabled who would live and who would die in the Action T4 euthanasia centers.
[4] The theme of the conference was the compulsory sterilisation of the "half Jews" (see also: Nuremberg Laws), which was to be offered as a "voluntary alternative" to deportation.
[5] Since 1941, Rodenberg had written of the castration of homosexuals in medical journals, which even earned him the recognition of Heinrich Himmler on 30 December 1942 for his "compelling articles".
Based on material collected while in the Kripo, in 1942 Rodenberg believed that he could demonstrate that castration was an appropriate measure "to remove criminal homosexual dynamics and at the same time help them", as stated in the journal Deutsche Justiz (German Justice).
In October 1942 he justified his proposal with the costs that resulted for the state for the support of homosexuals in Nazi concentration camps and preventative detention: "if they were castrated, they would be released soon, as most would not present a danger to the community, and they could also be reintegrated into society with the benefit of life".