The new definition would essentially eradicate federal recognition of the estimated 1.4 million Americans who have opted to recognise themselves - surgically or otherwise - as a gender other than the one they were born into.
The goal of the redefinition is to deny transgender people protection under federal civil rights law that prohibits discrimination on the basis of sex.
"Setting a destructive precedent, the Trump-Pence administration intends to erase LGBTQ people from federal civil rights protections and eviscerate enforcement of non-discrimination laws", the group's president, Chad Griffin, said in a statement.
Civil rights groups across the board have pledged to fight back.
The White House's new definition, if implemented, would mark a significant rollback of Obama-era policies that largely allowed people to choose how they identify rather than be determined by the sex assigned at birth.
Saudi king, crown prince send condolences to Khashoggi´s son
The American senators argue that in Saudi Arabia, things of high magnitude can not be done without clearance from the top. They made the mistake when they killed Jamal Khashoggi in the consulate and they tried to cover up for it", he said.
The Trump administration is facing backlash for reportedly considering defining a person's gender as the one identified at birth based on genitalia.
"The sex listed on a person's birth certificate, as originally issued, shall constitute definitive proof of a person's sex unless rebutted by reliable genetic evidence", the memo allegedly says. Trump might not recognize transgender people, but Twitter activists and allies will. Those who challenge the government definition legally would have to submit to genetic testing, according to the report.
The Department of Health and Human Services told U.S. media it will not comment on alleged document leaks.
The reported change is being spearheaded by the Department of Health and Human Services to establish a legal definition of sex under Title IX, the federal civil rights law that bans gender discrimination in education programs receiving government funding.
An HHS spokeswoman declined to comment on what she called "allegedly leaked documents" but cited a ruling by a conservative United States district judge as a guide to transgender policy.
Jordan demands Israel RETURN land leased under 1994 peace treaty
They signed a trade treaty in 1996 and in 2014, agreed to a $500 million natural gas deal effective for 15 years. The case of Baqoura could provide a predicament for Israel and Jordan given a possible dispute over land rights.
That's not very controversial, particularly for HHS subsidiaries, who have struggled to handle questions about gender-based discrimination that arise, specifically, under Title IX, which covers sex and gender issues at publicly funded colleges and universities.
Maj. David Eastburn, a Pentagon spokesman, said the announcement of a new policy would have no immediate practical effect on the military because the Pentagon has been obliged to continue to recruit and retain transgender people in accordance with current law.
It said additionally that HHS officials were looking to a 2016 federal court ruling on a provision of Obamacare, where Judge Reed O'Connor said, "Congress did not understand "sex" to include 'gender identity'".
Severino previously called the Obama administration's moves part of a "radical gender ideology".
Nikki Haley Roasts Elizabeth Warren For Failing DNA Test
Nikki Haley got in a few jabs of her own Thursday night. "Two years ago, Trump was here and made some waves with his remarks". Elizabeth Warren (D-Mass.) for appearing to have greatly exaggerated her Native American heritage, USA ambassador to the U.N.