Transgender individuals wishing to enlist in the US military are now free to openly do so, despite efforts by President Donald Trump to bar transgender personnel from serving "in any capacity."
As of January 1, the Pentagon is allowing transgender people to sign up, providing they meet certain medical criteria.
The milestone is the latest in a string of setbacks for Trump's ban, which he announced via Twitter last July, citing "tremendous" medical costs and disruption to the military.
Lawsuits playing out in four federal courts have resulted in rulings against the ban, putting its implementation on hold with judges saying it is likely unconstitutional.
Under a new policy first announced when Barack Obama was in power, the Pentagon was supposed to start accepting transgender recruits on July 1, 2017 but Secretary of Defense Jim Mattis pushed that back by six months to January 1, pending further review.
Last week, the Department of Justice said it would not ask the Supreme Court to prevent transgender people from entering the military, meaning the January 1 date went into effect.
"As mandated by court order, the Department of Defense is prepared to begin accessing transgender applicants for military service January 1, and all applicants must meet all current accession standards," Pentagon spokesman Major Dave Eastburn said.
All transgender recruits who have had gender reassignment surgery must have a doctor sign off that at least 18 months has elapsed since the date of the most recent surgery and that no additional surgeries are required.
Additionally, trans applicants must have "been stable in the preferred gender for 18 months," the Pentagon said.
"This is a victory for our country and all of the brave men and women who are transgender, and are ready, willing, and able to serve," said Joshua Block, an attorney with the American Civil Liberties Union.
On June 30, 2016, Obama's defense secretary Ash Carter said the military could no longer discharge or deny re-enlistment to troops based solely on their gender identity.
That meant transgender troops who were encouraged to come out under one administration suddenly faced getting booted under another.
But federal courts quickly ruled against such a move, saying the status quo should remain in effect.
Judges have also ruled against other aspects of Trump's ban, including that the military should continue to provide gender transition-related medical treatment for now.
A Pentagon panel of military and civilian experts is currently looking at the transgender issue and is expected to provide a new recommendation to Trump by the end of February.