Sex Matters is a UK-based not-for-profit organisation. We campaign, advocate and produce resources to promote clarity about sex in public policy, law and culture. We have a singular mission: to re-establish that sex matters in rules, laws, policies, language and culture.

Our vision

  • Sex matters. Organisations and the state should be clear that sex means biological sex. Being able to recognise reality in our language, rules and systems is essential to law making and enforcement, and to social organisation. It is essential to a functioning, cohesive society.
  • Individuals should be free to hold and express diverse beliefs, and to express themselves about sex and gender identity, without sanctions or being labelled hateful. 
  • Debates and deliberation about how best to accommodate and respect the human rights of people with different beliefs about gender identity should be undertaken openly, based on standard principles of democratic debate, evidenced analysis and human rights.

Our mission

We champion clarity about sex – in language, rules, laws, policies and culture, as a means to underpin everybody’s human rights. 

We support people to be clear about what sex means and when it matters in their own institutions, and to resist pressure towards ambiguity and dishonesty about sex, and to help them understand the laws that protect them. 

We hold organisations to account for communicating and implementing clear policies, making it easier for them to do the right thing. 

We campaign for laws, policies and practices that are clear about sex, and that enable people to live as they choose in relation to gender expression and beliefs about gender identity. 

We work with others campaigning on this issue to amplify their work and enable more people to get involved.

We will have an initial focus in the UK, but also engage internationally.

Our founders

Rebecca Bull is a solicitor specialising in equal pay and workplace discrimination. She started out assisting the Fair Play for Women 2018 campaign to inform and motivate the public to submit responses to the consultation on self-identification. She has researched, written and presented on the law around sex and gender reassignment, presented her paper on the Impact of Gender Recognition Reform on Sex Based Rights at the Scottish parliament in February 2020, and published articles in the top-tier UK law journal Modern Law Review (co-authored with Alessandra Asteriti), Scottish Legal News and the lawyers’ collective Legal Feminist.

Naomi Cunningham is a barrister specialising in employment and discrimination law. She was instructed in Fair Play for Women’s challenge to the ONS guidance on the sex question in the 2021 census. She is part of the lawyers’ collective Legal Feminist; she has written about sex and gender in sport, personal care, security staff guidance, puberty blockers and parental consent. In February 2021 she gave evidence to the Women and Equalities Select Committee on behalf of Legal Feminist.

Maya Forstater is a researcher, writer and advisor working on business and sustainable development. In 2019 she lost her job after tweeting and writing about sex and gender. She was the claimant in a landmark test case on whether the protected characteristic of belief in the Equality Act covers gender-critical beliefs. She writes about single-sex services at www.a-question-of-consent.net/. You can watch her speech at the 2020 Woman’s Place UK conference. Maya tweets at @MForstater.

Dr Emma Hilton is a developmental biologist at the University of Manchester, studying aspects of human genetic disease. She has a special interest in fairness in female sports and has written and presented on the evidence in relation to transwomen athletes and the rules on women’s sports, including giving input to World Rugby’s review of the evidence. She has written an op ed in the Wall Street Journal on sex denialism, and developed Project Nettie, a declaration on the basic science of sex by scientists. She joined the Sex Matters board in January 2021.