Updated at 5:15 pm ET
A memo that has reportedly been circulating at the Department of Health and Human Services aims to narrow the federal government's definition of "sex" under Title IX — a change that could leave transgender people without a number of the legal protections that have become standard in recent years.
The memo reported on by The New York Times has not been released publicly. NPR has not seen it, and HHS says it does not comment on "alleged leaked documents."
But the potential impact of the policies described in the memo, and the headline under which The Times ran its story — 'Transgender' Could Be Defined Out of Existence Under Trump Administration — inspired grave fears and fervent protest.
People gathered in New York City's Washington Square Park on Sunday evening to rally for trans rights, and protesters on Monday rallied in front of the White House holding signs that declared, "We will not be erased."
Many trans people began posting photos of themselves to social media, using the hashtag #WontBeErased.
"We're here. We're loud. We're not going anywhere. #WontBeErased," tweeted the National Center for Transgender Equality.
The Times reports that the document was written in the spring and proposes that different government agencies adopt a unified definition of sex — specifically one that defines it as determined "on a biological basis that is clear, grounded in science, objective and administrable."
"The agency's proposed definition would define sex as either male or female, unchangeable, and determined by the genitals that a person is born with," The Times reports, based on the draft seen by its reporters. "Any dispute about one's sex would have to be clarified using genetic testing."
Title IX is the federal law passed as part of the Education Amendments of 1972 that prohibits discrimination on the basis of sex "under any education program or activity receiving Federal financial assistance." The term "sex" refers to gender, which has since been expanded under the law to include sexual orientation and gender identity.
It's not clear who drafted the memo, but The Times reports that it is part of an effort by the HHS to establish a uniform definition accepted by the four agencies that enforce Title IX: the departments of education, justice, HHS and labor.
At the White House on Monday, President Trump was asked about his earlier promise to protect transgender Americans and others in the LGBTQ community.
"We're looking at it," Trump replied. "We have a lot of different concepts right now. They have a lot of different things happening with respect to transgender right now."
"I'm protecting everybody," he added. "I want to protect our country."
"I am a #transgender person. I am livid but clear-headed. I am threatened but absolutely resolute. @transequality will always fight," wrote Mara Keisling, executive director of the National Center for Transgender Equality.
"I know folks are scared and hurt. So am I. We are working to stop this and we will never give up. The courts are scary. The administration is scary. This world is scary. We still have tools. I am here. I see your beautiful humanity. And I love you," tweeted Chase Strangio, an attorney with the ACLU's LGBT and AIDS Project.
The Trump administration already has taken steps to try to disqualify most transgender people from serving in the military.
Earlier this month, the State Department implemented a policy denying visas to same-sex partners of foreign diplomats and the staff of U.S.-based international organizations if they are not legally married. Many of the affected couples are from countries where same-sex marriage is illegal.
NPR health policy correspondent Alison Kodjak contributed to this report.