This article examines the advice columns of a Spanish anarchist periodical, La Revista Blanca, in the 1930s. It considers how this example of interactive media, influenced by wider European scientific discourses including eugenics, contributed to shaping anarchist socio-sexual morality. By analysing the periodical's discussions of bodies, birth control, and ‘free love’, the article draws attention to anarchism's inherent tension between the free will of individuals and their obligations to collective progress. It asks how this tension played out at the intersection between anarchist sexual revolution and ‘women's emancipation’, and by extension how we might situate anarchist women in ‘feminist’ history.