“Girlguiding believes strongly in inclusion, and we will continue to support young people and adults in marginalised groups.”
In UK law, the 2010 Equality Act sets out the rules for single sex organisations and spaces being able to exclude members of the opposite sex.
In April, the Supreme Court ruled that this meant biological sex, meaning, for example, that a trans man could be excluded from a service set up for men.
Draft guidelines on how to interpret the law by the equality watchdog, the Equality and Human Rights Commission (EHRC), were presented to the government for consideration in September. A leaked copy was reported on last week, but it has not been officially published.
Girlguiding said it has made its decision following consultation with members and legal advice. It will now allow only biologically female members to join.
It said: “Girlguiding’s governing charity documents set out that the membership and people who benefit from our organisation are girls and women.”
The organisation was reportedly facing legal action from a parent who felt it was failing to follow the law.
Biological girls who identify as boys are still able to join.
The organisation also said most adult roles were already open to all and it was “confident that no volunteers will have to leave”.
Other adult roles are already designated specifically as female roles.