Richard Freiherr von Krafft-Ebing was a German psychiatrist and author of the foundational work Psychopathia Sexualis (1886).

Magnus Hirschfeld was a Jewish German physician and sexologist, whose citizenship was later revoked by the Nazi government. Hirschfeld was educated in philosophy, philology and medicine. An outspoken advocate for sexual minorities, Hirschfeld founded the Scientific-Humanitarian Committee and World League for Sexual Reform. He based his practice in Berlin-Charlottenburg during the Weimar period. Performance Studies and Rhetoric Professor Dustin Goltz characterized the committee as having carried out "the first advocacy for homosexual and transgender rights".