(Photo credit: John Shearer/Getty Images | GLAAD/YouTube)

Stephen Ira Beatty, the oldest child of Warren Beatty and Annette Bening, is speaking out about a cause close to his heart: health care for transgender people.

Beatty, 21, a transgender male, has been an advocate for the LGBT community for years.

"I grew up outside of New York, but I've known I've wanted to move there for the city's vibrant artistic community," he said in a new GLAAD-sponsored public service announcement. "As a trans person, I would hope that I'd be welcomed, but many trans people aren't because we don't have the basic health care coverage we need to survive."

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Last year, Beatty made a video in which he said, ""My name is Stephen. I identify as a trans man, a … queen, a homosexual, a queer, a nerd fighter, a writer, an artist and a guy who needs a haircut." He added that he began transitioning from female to male at age 14.

Eventually, he said, he'd like to "write poetry and fiction and critical work," to encourage open-mindedness. Also, "I am going to have babies," he said, "and give them onesies with 'This is what a transfeminist looks like' on them."