The attorney general, Suella Braverman, has said schools do not have to accommodate children who want to change gender under current legislation.
The government is drawing up formal guidance for schools on gender dysphoria and children who identify as transgender.
In an interview with the Times, Braverman QC said the law stated that under-18s could not legally change their sex, enabling schools to treat all of their pupils by the sex of their birth.
The Conservative MP for Fareham said: “Under-18s cannot get a gender recognition certificate, under-18s cannot legally change sex. So again, in the context of schools, I think it’s even clearer. A male child who says in a school that they are a trans girl, that they want to be female, is legally still a boy or a male. And schools have a right to treat them as such under the law.