Children who believe they are transgender face new curbs on gender reassignment treatment to protect them from “irreversible” decisions.

Liz Truss, the trade secretary, told MPs that the wellbeing of under-18s was a key principle that would guide her response to a review of government policy on gender identity.

Ms Truss, who is also minister for women and equalities, said that analysis of feedback to a consultation on the future of the Gender Recognition Act was complete.

There had been speculation that Boris Johnson would abandon this work to avoid a row with activists but Ms Truss said she would announce changes before the summer, including restrictions on treatment for transgender children.

“Grown adults should be able to make decisions, to have agency to live life as they see fit,” she said. “But before the age of 18, when people are still developing their decision-making capabilities, they should be protected from making decisions that are irreversible about their bodies that they could possibly regret in the future.”

She said that the freedom of transgender adults would be upheld “whilst maintaining the proper checks and balances of the system”.

Officials would not discuss the planned protections for children but said that they would form part of Ms Truss’s announcement.

The Gender Recognition Act 2004, which allows transgender people in England and Wales to have their chosen identity legally recognised including with a new birth certificate, applies to adults only at present. Rules on treatment for children with gender dysphoria will be set out alongside changes to the act.

Ms Truss told the Commons women and equalities committee that there would also be additional protection of single-sex spaces to ensure that women and girls were safe in places such as changing rooms and lavatories as well as women’s refuges, by excluding other people where necessary.