Kemi Badenoch is considering changing the Equality Act to allow organisations to bar trans women from single-sex spaces and events, including hospital wards and sports. The change by the equalities secretary would redefine sex in the 2010 act to specifically refer to legal protections for “biological sex” – the sex assigned at birth. Badenoch asked the Equality and Human Rights Commission (EHRC) to advise on the change, it emerged on Tuesday. The equalities watchdog said the new definition would make it possible to exclude trans people from same-sex spaces even if they hold a gender recognition certificate (GRC). The recommendation was welcomed by the gender-critical campaign group Sex Matters, but prompted anger from the LGBTQ+ group Stonewall, which said it “risks opening yet another chapter in a manufactured culture war that will see little benefit to women, cis and trans alike”. Government sources said they were looking carefully at the EHRC response, warning the legislation was complicated. But Badenoch is being backed by Downing Street to continue looking at the possibility of a change. In a letter to Badenoch published on Tuesday, the EHRC said the change would extend protections for trans men who use maternity services, as they would have rights based on their biological sex. Seven other implications of the change, as cited by the watchdog, would make it simpler for groups and services to exclude trans people even if they hold an official certificate recognising their gender. Badenoch had written to the EHRC earlier this year to ask them to provide their view on whether sex, a protected characteristic under the 2010 Equality Act, would benefit from clarification that it refers to biological sex. The EHRC said the government should carefully consider that any change could have “possible disadvantages for trans men and trans women”. Its letter said: “There is no straightforward balance, but we have come to the view that if ‘sex’ is defined as biological sex for the purposes of EqA, this would bring greater legal clarity.” The EHRC said currently sex was defined as legal sex, meaning that the protected group included those with a gender recognition certificate. Changing to a biological definition would mean single-sex groups could then restrict membership to biological women or men, the EHRC said, giving the example of lesbian groups or women’s-only book groups, which would be able to then exclude trans people. It also says political parties could restrict trans women with a GRC from benefiting from “women-only” shortlists and other measures aimed at increasing female participation. The EHRC said it was a “perceived anomaly” that trans men could not benefit but trans women could. The change would also allow employers to restrict positions to biological women or men, with the EHRC giving the example of a warden in a women’s or girls’ hostel. A biological definition of sex would also mean hospitals could restrict trans women from certain female wards, though the EHRC said a service provider “would have to conduct a careful balancing exercise to justify excluding all trans women”. And it said organisers would more easily be able to exclude trans women with a GRC from women’s sports without having to prove that it was necessary to do so in the interests of fairness or safety. The letter also warned that there were areas in which the change could have unintended consequences, such as making it easier for trans men to bring pay discrimination claims but not trans women, because they could claim on the basis of biological sex. The EHRC’s chair, Kishwer Falkner, said the change “could bring clarity in a number of areas, but potential ambiguity in others”. “Our response to the minister’s request for advice suggests that the UK government carefully identify and consider the potential implications of this change,” she said. “There is a clear need to move the public debate on issues of sex and gender to a more informed and constructive basis. This would be welcomed by the many who do not take the polarised positions currently driving public debate.” The EHRC said there was also a clear need to evolve the language used in the 2010 act, which “refers to trans people as ‘transsexuals’, and uses the terms ‘sex’ and ‘gender’ at times interchangeably, with the requirement on employers to report ‘gender pay gaps’ in fact a duty to report on pay differences according to the protected characteristic of sex”. Stonewall said the letter from the EHRC offered “no substantive evidence of demand for this work” and said the group did “not see a world where cis women are desperate to exclude trans women from their spaces”. “The EHRC is right to consider how trans men miss out on provisions and protections, but it is fundamentally wrong to imply that trans women do not experience sexism, which cuts far beyond biology,” a spokesperson said. “We would also expect the EHRC to make further reference to some of the challenges defining ‘biological’ sex, discussion around how these measures would interact with the Equality Act’s protection for people who are ‘perceived’ to hold protected characteristics, and how rights for intersex people might be considered.” Sex Matters, which started a petition to amend the Equality Act, said: “This is a measured and thoughtful analysis from the EHRC. We are confident that our proposed amendment will deliver substantial improvements in clarity and fairness, but for now we are content with the conclusion that it merits further consideration.”