The complaint argues that the order discriminates against transgender people.Trump signed an executive order last month directing federally run insurance programs, including Medicaid and TRICARE for military families, to exclude coverage for such care.
It also calls on the Department of Justice to pursue litigation and legislation to oppose it.Medicaid programs in some states cover gender-affirming care.
The new order suggests that the practice could end, and targets hospitals and universities that receive federal money and provide the care.
At least 26 states have passed laws to restrict or ban the care for minors.
The U.S. Supreme Court heard arguments last year but has not yet ruled on whether Tennessee's ban on the care is constitutional.

Trump policies on gender-affirming care and passports for transgender people challenged in court