The Biden administration announced expansive new protections on Friday for gay and transgender medical patients, prohibiting federally funded health providers and insurers from discriminating on the basis of sexual orientation and gender identity.

The new rule reverses a policy instituted by the Trump administration and helps to fulfill part of President Biden’s vow to restore civil rights protections for L.G.B.T.Q. people that were eliminated by his predecessor.

“Today’s rule is a giant step forward for this country toward a more equitable and inclusive health care system, and means that Americans across the country now have a clear way to act on their rights against discrimination when they go to the doctor, talk with their health plan or engage with health programs run by H.H.S.,” Xavier Becerra, the health and human services secretary, said in a statement.

The rule overhauls federal policy in an area that has become a political flashpoint, with more than 20 Republican-led states banning or restricting gender-affirming care for minors in recent years, and it is likely to draw legal challenges. Even the history of the rule illustrates the political sensitivities at play: It has now taken three different forms under three successive presidents.

The Affordable Care Act, passed in 2010, established a sweeping set of civil rights protections in the U.S. health system through what is known as Section 1557. It prohibits discrimination against patients based on race, color, national origin, sex, age or disability in “any health program or activity” that receives federal funds, covering a broad swath of the U.S. health system.