Background With the rise in salience of the concept of gender identity, changes are being made to language and data collection with major implications for women’s health research and equality. Specifically, language referring to women is being desexed and data collection on sex diminishing. In 2023, Australia’s National Health and Medical Research Council (NHMRC) undertook public consultations on two draft guidance documents discussing use of the words 'woman'/'women' when describing the involvement of pregnant women in research, and sex and gender identity data collection. We collaborated in writing and gathering support for responses to both consultations.

Discussion We advocated retaining sexed usage of woman/women when sex was relevant, emphasising that addressing sexism and the female data gap requires identifying women as a group and emphasised the need to avoid confusion, dehumanisation, and exclusion of disadvantaged groups. We expressed concern that data collection on gender identity is supplanting that on sex, and sex data is not being accurately collected. We recommended the NHMRC prioritise data accuracy, guide researchers on when and how to collect sex data, and recognise that individuals do not universally apply gender identity to themselves. These issues have international relevance as pressure to desex language and prioritise gender identity data is occurring world-wide. The NHMRC has now finalised its data collection guidance, unfortunately our concerns were largely ignored.

Conclusion Researchers and clinicians globally must urgently participate in policy discussion regarding the importance of sexed language and accurate sex data, to protect individual and population health and data and research integrity.