SAN FRANCISCO — Before handcuffing herself to the White House fence, former Petty Officer 1st Class Autumn Sandeen carefully pinned three rows of Navy ribbons to her chest. Her regulation dress blue skirt, fitted jacket, hat, and black pumps were new — fitting for a woman who spent two decades serving her country as a man.

Sandeen was the only transgender person among the six veterans arrested in April while protesting the military’s ban on openly gay troops. But when she watched President Obama sign the hard-fought bill allowing for the ban’s repeal, melancholy tinged her satisfaction.

“This is another bridesmaid moment for the transgender community,’’ the 51-year-old San Diego resident said.

The “don’t ask, don’t tell’’ policy now heading toward history does not apply to transgender recruits, who are automatically disqualified as unfit for service. But the military’s longstanding posture on gender identity has not prevented transgender citizens from signing up before they come out, or from obtaining psychological counseling, hormones, and routine health care through the Department of Veterans Affairs once they return to civilian life.

As the Pentagon prepares to welcome openly gay, lesbian, and bisexual service members, Sandeen is not alone in hoping the United States will one day join other nations that allow transgender troops.

“There is really no question, it’s just a matter of when,’’ said former Army Captain Allyson Robinson, 40, a West Point graduate who has spoken to sociology classes at the academy she attended as a male cadet.

No one knows how many transgender people are serving or have served. But the Transgender American Veterans Association, an advocacy group founded in 2003, estimates there could be up to 300,000 transgender people among the nation’s 26 million veterans.

Military regulations state that men and women who identify with or present a gender different from their sex at birth have mental conditions that make them ineligible to serve. Those who have undergone genital surgery are listed as having physical abnormalities.

Until the American Psychiatric Association removes gender identity disorder from its Diagnostic and Statistical Manual of Mental Disorders, as it did for homosexuality in 1973, that is likely to remain the case, Sandeen said.

The very diagnosis that keeps transgender Americans out of uniform has enabled some to obtain transition-related medical care and other services when they become veterans.

Sandeen said the veterans hospital in San Diego made it possible for her to start living as a woman once she retired from the Navy a decade ago.

“As soon as I got an appointment with the psychiatry department, the first thing I said to them is, ‘I have gender issues. I don’t know if I’m a transvestite or a transsexual or if I’m something in between, but I need to work this out with a therapist,’ ’’ she recalled.

She eventually received a recommendation to see a veterans health doctor who could prescribe estrogen.

Sandeen had lined up a work-study job at the hospital’s patient health library.

“February 6, 2003, my first day of being publicly female, I was working for $10 an hour at the VA helping other vets with health care needs,’’ she said.

© Copyright 2011 Globe Newspaper Company.