This study explores the meanings ascribed to sexual difference in the theories of Charles Fourier, the Saint-Simonians and Flora Tristan. Their concept of 'the feminine' as a moral force justified a wide range of social roles for women. In addition, 'the feminine' became a symbol of the harmony and co-operation envisaged for the future. The study shows that, while these socialists challenged contemporary sex-role definitions, the new distinctions which they created nevertheless circumscribed the possibilities for female 'liberty'.