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.

In 2016, the Obama administration issued a less expansive version of the rule the Biden administration finalized on Friday, requiring health providers to provide medically appropriate treatment for transgender patients. Officials at the time argued that the Affordable Care Act’s protections against discrimination included gender identity. The Obama rule became tied up in litigation, and the Trump administration declined to enforce it.

Conservative opponents of the rule have argued that the policy could effectively coerce doctors into performing medical services that they might have objected to, including on religious grounds. The Trump administration in 2020 formally narrowed the legal definition of sex discrimination to not include protections for transgender people.

The rule finalized by the Biden administration on Friday states that it preserves religious exemptions and “does not require or mandate the provision of any particular medical service.”

“Section 1557 prohibits discrimination on certain prohibited bases, and does not interfere with individualized clinical judgment about the appropriate course of care for a patient,” the rule says.

After the Supreme Court ruled in 2020 that the Civil Rights Act of 1964’s prohibition on discrimination based on sex also applied to discrimination based on sexual orientation and gender identity, the Biden administration began to reverse the Trump administration policy.

Republican officials continued to work to preserve the Trump-era rule. In 2022, after the Biden administration issued a proposed version of the rule it finalized on Friday, a group of Republican attorneys general wrote to Mr. Becerra, suggesting they could sue if the Health and Human Services Department pursued the policy.

The rule proposal drew intense scrutiny from advocates and opponents. The Health and Human Services Department said on Friday that it had garnered more than 85,000 comments.

Groups that pushed for the reversal of the Trump-era rule hailed the Biden administration’s decision on Friday. “Countless Americans can now find solace in knowing that they cannot be turned away from health care they need just because of who they are or who they love,” said Kelley Robinson, the president of the Human Rights Campaign.