Marhoefer's research focuses on Weimar and Nazi Germany and queer and transgender politics (circa 1890s-the present) in Europe and the United States. Themes in Marhoefer's writing include the rise of the Nazis and the nature of fascism, racism in politics (including in LGBTQ politics), the AIDS crisis of the 1980s, how democracies fall apart and become dictatorships, and queer and transgender activism. Marhoefer has consulted for Politifact and Pew Research on the history of Nazism and been a guest on NPR and on public radio in New Zealand.
Charts the rise of the world's first queer and trans rights movements (in Germany in the 1920s) and examines what that movement had to do with the rise of fascism and the fall of democracy.
Argues that gender non-conforming people and queer women ran risks under fascism even though the law against homosexuality only applied to men. Discusses this through the story of one person under investigation by the Gestapo.