The English High Court of Justice on Tuesday ruled against the Tavistock clinic, the National Health Service’s (NHS) sole gender clinic, in favor of Keira Bell, a 23-year-old woman who said she was harmed by puberty blockers and cross-sex hormones prescribed to her when she was a teenager.

“It is highly unlikely that a child aged 13 or under would be competent to give consent to the administration of puberty blockers,” the judges agreed in the ruling. “It is doubtful that a child aged 14 or 15 could understand and weigh the long-term risks and consequences of the administration of puberty blockers.”

The court also ruled that it would be appropriate for clinicians to involve the court in any case where there is doubt as to whether the long-term interests of a 16- or 17-year-old would be served by the interventions of blockers and hormones.

Bell, along with another unnamed claimant, brought the suit against the Tavistock and Portman NHS Trust, which operates the gender identity development service. She said she began taking puberty blockers when she was 16, was injected with testosterone at 17 and had a mastectomy at 20 before deciding to “de-transition” last year.

Bell argued she was treated like a “guinea pig” at the clinic, and said doctors failed to carry out a proper psychiatric assessment and should have challenged her more over her decision to transition to a male as a teenager.

The NHS had previously claimed that puberty blockers are ‘fully reversible.” But in June, it quietly changed its website to say that hormone blockers “cause some irreversible changes” and may lead to “permanent infertility.”

Bell said that she is experiencing this firsthand, as she now lives with the scars from her transition surgeries and continues to have a deepened voice as a result of testosterone. She also believes the gender-transition drugs likely made her sterile.

The other claimant, known only as Mrs. A, is reportedly the mother of a 15-year-old autistic girl who is on the waiting list for treatment at the clinic.

After the decision was announced, Bell told the press, “This judgment is not political, it’s about protecting vulnerable children.

“I’m delighted to see that common sense has prevailed,” she continued. “It exposes a complacent and dangerous culture at the heart of the national center responsible for treating children and young people with gender dysphoria.”

As a result of the ruling, an NHS spokesperson said, “The Tavistock have immediately suspended new referrals for puberty blockers and cross-sex hormones for the under 16s, which in future will only be permitted where a court specifically authorizes it.”

Paul Conrathe, the lawyer who represented both claimants, said the ruling was “an historic judgment that protects children who suffer from gender dysphoria.

“This may have led to hundreds of children receiving this experimental treatment without their properly informed consent,” he said.