What is the legal definition of biological sex? New trans law explained after Badenoch’s announcement

The Conservatives have pledged to change the law if they win the general election so that transgender people could be legally excluded from single-sex spaces.

Kemi Badenoch says the government would change the 2010 Equality Act and change the definition of sex to reflect biological sex that is given at birth.

It is against the law to discriminate against someone based on their sex, as it is a protected characteristic. The new rules are designed to make clear that this refers only to the sex given to a person at birth.

Under the Equality Act, some limited ‘discrimination’ is still allowed to enable single-sex services such as rape crisis centres, domestic abuse support services, or women’s prisons.

Ms Badenoch says the legislation is aimed at protecting women in these spaces. The proposed changes would enable organisations to bar male-bodied people from single-sex services or activities without breaking the law.

“Whether it is rapists being housed in women’s prisons, or instances of men playing in women’s sports where they have an unfair advantage, it is clear that public authorities and regulatory bodies are confused about what the law says on sex and gender and when to act – often for fear of being accused of transphobia, or not being inclusive,” the Women and Equalities Minister said.

“That is why we are today pledging that, if we form a government after the election, we will clarify that sex in the law means biological sex and not new, redefined meanings of the word. The protection of women and girls’ spaces is too important to allow the confusion to continue.”

Speaking on BBC R4’s Today programme, Ms Badenoch explained that the legislation aims to “create a chilling effect for those men who are predators, who are exploiting trans people and are exploiting laws we have put in place to protect trans people.”

The changes would also make gender recognition a reserved matter which only Westminster can legislate on. This comes after Scotland’s Gender Recognition Reform Bill was blocked by the UK government in 2023 for clashing with UK-wide legislation.

The 2010 Equality Act defines sex in binary terms as ‘a reference to a man or woman’.

Put simply, the legal definition of biological sex is what’s written on your birth certificate – but this can be changed.

A trans person can change their legal sex by obtaining a Gender Recognition Certificate. This will amend the sex category on their birth certificate, with a note that it has been changed.

A person must apply to the Gender Recognition Panel to acquire this certificate. The applicant needs to obtain a medical report written by a licenced doctor or psychologist specialising in gender dysphoria.

There are then a few routes depending on the circumstances. Generally, a person must be diagnosed with gender dysphoria (a discomfort with their birth gender) or have had surgery to change their sexual characteristics. They must also have lived in their acquired gender for two years, or intend to for the rest of their live.

The applicant cannot be under 18.

The ability to change legal sex was enshrined in the 2004 Gender Recognition Act, following an intervention by the European Court of Human Rights.

It was designed to allow people to choose the sex they feel matches their gender identity, granting them the human right to respect for private life.

“Sex is biological, and gender is psychological and social,” says Silva Neves, a psychotherapist and spokesperson for the UK Council for Psychotherapy (UKCP).

“Biological sex is typically male or female, but more diverse biology is observed, for example, with people with intersex characteristics.

“Gender, however, is how someone feels inside, which may or may not match their biology because gender is much broader than genitals and sex characteristics.

“A great majority of non-binary and transgender people have significant improved psychological wellbeing when they live in harmony with their gender identity.”