Abstract In the early twentieth century a large network of organizations, co-ordinated by the Association for Moral and Social Hygiene (AMSH), campaigned for changes to the law on sexual offences. In particular, they sought to strengthen age-of-consent law for the protection of young girls. Their efforts resulted in a Criminal Law Amendment Bill in 1921 which would have raised the age of consent for indecent assault and removed significant weaknesses in the existing legislation which made prosecutions difficult. However, there was active opposition to the Bill, often anti-feminist in tone. An amendment creating an offence of ‘gross indecency between females’ was introduced by these opponents. If enacted, it would have made all sexual activity between women criminal. The amendment, designed to directly attack the Bill and its feminist supporters, not only led to the Bill’s failure but also posed difficulties for the AMSH and others in formulating a response. Above all, lesbianism was considered publicly unspeakable, as the parliamentary debates themselves made clear. What answer could respectable women therefore make? This article explores the responses of the Bill’s supporters, particularly the AMSH.