Story highlights Frank Kameny died peacefully of natural causes, his sister says

Kameny, who served in WWII, fought against the Army's policy of discharging homosexuals

He urged what was then called the homophile movement to assert itself to achieve equality

He worked to end homoexuality's classification as a mental illness

Pioneering gay rights activist Frank Kameny died Tuesday evening at home in Washington, a spokesman said. He was 86.

"He said everyone needs to know they are of value and respected, and by saying, 'Gay is good,' he thought that reflected that feeling. He wanted dignity and self-respect, and that's what he fought for," according to Bob Witeck of the Kameny Papers Project.

Kameny died peacefully of natural causes, according to his sister Edna Kameny Lavey.

He was at a Human Rights Campaign dinner a week ago in a wheelchair, she said.

"Frank Kameny led an extraordinary life marked by heroic activism that set a path for the modern LGBT civil rights movement," Human Rights Campaign President Joe Solmonese said in a statement. "From his early days fighting institutionalized discrimination in the federal workforce, Dr. Kameny taught us all that 'Gay is Good.'

"As we say goodbye to this trailblazer on National Coming Out Day, we remember the remarkable power we all have to change the world by living our lives like Frank -- openly, honestly and authentically," said Solmonese, whose group works for lesbian, gay, bisexual and transgender rights.

A seat at the front of the audience was reserved for Kameny when President Barack Obama in December 2010 signed into law the repeal of "don't ask, don't tell," which banned gay men and lesbians from serving openly in the U.S. armed forces.

Kameny attended the ceremony wearing the Combat Infantryman Badge that he was awarded for his service in World War II. Kameny recalled his service fighting in the wake of the Battle of the Bulge: "I dug my way across Europe slit trench by slit trench, practically."

But Kameny was not invited because of his heroism in World War II, but for his work toward changing the military policy of discharging homosexuals.

Kameny, who had been discharged from the Army Map Service in 1957 for being gay, led a demonstration at the Pentagon in 1965. Kameny called upon the nascent gay rights movement to model itself upon the civil rights movement.

The homophile movement, as it was called at the time, said that homosexuals were triply condemned: The medical establishment deemed them mentally ill, the law made them criminals and religions branded them sinners.

At a time when lesbians and gay men were so ostracized, the homophile movement decided its best tactic was to embrace the label of sickness: at least that seemed a half-step up from being criminals. But Kameny argued that such an approach was counterproductive, and that gay people should demand equality with heterosexuals. To gain equality, he argued, the movement needed to assert itself.

Kameny led the way in tactics such as public demonstrations, went on the attack against the Civil Service Commission for its policy of firing homosexuals, and spearheaded an effort to get the homophile movement to take the position that homosexuality was not only not a mental illness but was on a par with heterosexuality.

In 1968, he got the only existing national association of gay rights organizations to adopt as its slogan a phrase that Kameny had coined, "Gay is Good."