The policy shift, long-sought by the president’s religious and socially conservative supporters, defines gender as a person’s biological sex. The Obama regulation defined gender as a person’s internal sense of being male, female, neither or a combination.

LGBTQ groups say explicit protections are needed for people seeking sex-reassignment treatment, and even for transgender people who need medical care for common conditions such as diabetes or heart problems.

Behind the dispute over legal rights is a medically recognized condition called “gender dysphoria” — discomfort or distress caused by a discrepancy between the gender that a person identifies as and the gender at birth. Consequences can include severe depression. Treatment can range from sex-reassignment surgery and hormones to people changing their outward appearance by adopting a different hairstyle or clothing.

Many social conservatives disagree with the concept.

Women’s groups say the new regulations also undermine access to abortion, which is a legal medical procedure.

“No one should fear being turned away by a medical provider because of who they are or the personal health decisions they have made,” said Fatima Goss Graves, president of the National Women’s Law Center, raising the threat of a court challenge.

The ACLU has also said it would sue to overturn the Trump rule.

Under the Obama-era federal rule, a hospital could be required to perform gender-transition procedures such as hysterectomies if the facility provided that kind of treatment for other medical conditions. The rule was meant to carry out the anti-discrimination section of the Affordable Care Act, which bars sex discrimination in health care but does not use the term “gender identity.”

Roger Severino, head of the Health and Human Services Department unit that enforces civil rights laws, has said transgender people continue to be protected by other statutes that bar discrimination in health care on account of race, color, national origin, age, disability and other factors.

For the administration it’s the latest in a series of steps to revoke newly won protections for LGBTQ people in areas ranging from the military to housing and education.

The administration also has moved to restrict military service by transgender men and women, proposed allowing certain homeless shelters to take gender identity into account in offering someone a bed for the night, and concluded in a 2017 Justice Department memo that federal civil rights law does not protect transgender people from discrimination at work.

The proposed new rule would also affect the notices that millions of patients get in multiple languages about their rights to translation services. Such notices often come with insurer “explanation of benefits” forms. The Trump administration says the notice requirement has become a needless burden on health care providers, requiring billions of paper notices to be mailed annually at an estimated five-year cost of $3.2 billion.