The Federal Trade Commission and four states filed a lawsuit on Wednesday against a leading international group that writes guidelines on gender-related medical treatments, claiming that the group used questionable evidence to ensure that its services would be covered by medical insurers.
The legal action, filed in Texas, reflects an escalation in the Trump Administration’s efforts to put an end to gender-related care for minors across the nation. While the administration has already threatened to pull funding from hospitals that deliver such treatments, this effort targets guidelines that have provided a basis for health insurance coverage of the treatments.
The lawsuit takes aim at the World Professional Association for Transgender Health, or WPATH, and its U.S. counterpart. Those nonprofit organizations, made up of medical experts, issued an updated version of care standards in 2022, a document that drew scrutiny for omitting age limits for procedures including breast augmentations, genital surgeries and hysterectomies.
Joe Simonson, director of public affairs at the Federal Trade Commission, said in a media call on Wednesday that parents and children had been misled about the necessity, safety and scientific basis of gender-transition treatments in order to secure insurance coverage.
The states of Alaska, Iowa, Nebraska and Texas joined the lawsuit.
The F.T.C. lawsuit comes after a federal judge in Washington, D.C., last month blocked the agency from enforcing administrative subpoenas it had issued to WPATH, demanding records of communication between its members. In that case, Judge James E. Boasberg ruled that the group was likely to succeed on its First Amendment retaliation claim against the F.T.C.
In a statement, WPATH said the F.T.C. “has no place interfering with the process of individualized medical decision-making.”
Gender-transition treatment often involves puberty-delaying medication followed by hormone therapy to align physical traits like body hair and voice range with an adolescent’s gender identity. In rarer cases, treatment can include surgery.
The treatments are barred for minors in about half of the United States, including the four that joined the F.T.C. lawsuit. In states where the treatments are legal for minors, many pediatric clinics and hospitals have stopped providing them, citing pressures from the Trump administration.
An estimated 724,000 minors aged 13 to 17 in the United States identify as transgender, according to the Williams Institute, which researches the L.G.B.T.Q. population. That amounts to about 3 percent of the U.S. population in that age group. A small fraction of them receive medication for gender transition, experts say.
Wednesday’s lawsuit is the latest step by Andrew Ferguson, the chairman of the F.T.C., to turn the agency into an enforcer of President Trump’s priorities. Mr. Ferguson has explicitly rejected the agency’s traditional independence from the White House, taking actions that wade into culture war issues while testing the boundaries of the commission’s legal authority.
The F.T.C. last year opened an investigation into whether Media Matters, a nonprofit active in liberal politics, had illegally colluded with advertisers. Those concerns echoed claims by Elon Musk that the nonprofit had tried to hurt the relationship that his social media platform, X, has with advertisers. But a judge blocked the inquiry, saying the F.T.C. had retaliated against Media Matters for speech protected by the First Amendment. The two sides settled this year.
Mr. Ferguson has made scrutinizing gender-transition care a core priority since Mr. Trump appointed him last year. Last February, Amazon reinstated a book critical of such care, which it had previously banned as hate speech, after Mr. Ferguson questioned the ban on social media. Mr. Ferguson also hosted a forum for critics of pediatric gender-transition treatments last year.
