As the Washington National Opera performed onstage at the Kennedy Center one night last week, five professional actors and a director huddled in a rehearsal room above, discussing the play they will perform there next month. They parsed the Shakespeare references, analyzed the characters' complicated relationships and marveled at the subtle powers of a story in which the title character never appears.

Meanwhile, the playwright was in a Target store in Chicago, shopping for computer cables. With his mother. For his dorm room.

At 18, Paul Baumbusch, a McLean High School graduate about to begin his freshman year at Northwestern University, is experiencing the kind of showcasing that many older playwrights only dream about. The winner of two awards for high school acting, he recently beat out 174 scripts from 275 other high school and middle school students nationwide (some plays had more than one author) to win this year's Playwright Discovery Award, given by the nonprofit organization VSA arts for plays that address disability.

The awards ceremony Oct. 4 will include a full performance of Baumbusch's play "The Changeling," about a mother who, unable to handle her autistic son, blithely pushes the responsibility onto her teenage daughter.

"As soon as I read it, I thought, 'Oh, my God, this is so sophisticated,' " said Paul-Douglas Michnewicz, who is directing the play and was a preliminary judge for the award. "It treats all the characters so three-dimensionally."

Other judges included Jack Hofsiss, the Tony Award-winning director of "The Elephant Man"; and Fred Zollo, who has won several Tonys, including one for producing "Private Lives," and produced the films "Mississippi Burning" and "Quiz Show." In the contest's 20 years, winning entries have dealt with such subjects as blindness, spinal cord injury, lupus and albinism. The committee usually selects two winners, but this year it stopped at one.

"They did feel this was such a gem," said Elena Widder, director of performing arts for the organization. "It was the first quote-unquote 'real' play we've had in such a long time."

Baumbusch got the idea after seeing his voice teacher cope -- albeit more gracefully than his lead character -- with her autistic son. It is not the first play he has written about a disability; he wrote one last year that won a Scholastic Gold Award, about a middle-age woman whose body is being destroyed by Lou Gehrig's disease. Baumbusch himself is tall and lanky ("very swarthy" and "rakish," as he puts it) with no visible handicaps. So how did so young a writer come up with such affecting material about these painful subjects?

"I think it's honestly because I'm gay," he said, confidently broaching the topic via cell phone while trolling through a household goods store with his mother. It is something he has been used to discussing in public since his sophomore year of high school, when he wrote a letter to the McLean High School newspaper disclosing his sexual identity. After that he became somewhat of a spokesman for gay high school students in the Washington area.

Gay teenagers often feel trapped in their bodies, he said, something he compares with the feelings a physical disability can bring on. "There's so much self-loathing among gay teens," he said. Because so few people come out at that age, he explained, "it almost guarantees you will never find young love."

Baumbusch's peers and faculty at McLean were largely supportive -- in fact, he said, he got less teasing after he came out than before. Still, he never found a boyfriend, either there or at Interlochen Center for the Arts, the fine arts academy in Michigan where he spent his last year of high school. "I was given the kind of mark of Cain: continuous isolation and safe passage through high school," he said. With no gay friends, and straight friends who didn't really understand what he was going through, he said, "it's a lonely four years. You spend a lot of it saying, 'Why am I lonely? It must be my fault.' "

Equating homosexuality and disability risks upsetting people in both categories; indeed, Widder was quick to note that VSA arts doesn't share Baumbusch's view. But it is a perspective he has honed over the years, on long walks with his little white dog, Fred ("We think he's gay, too"), and he defended it with a carefully phrased soliloquy:

"This will offend probably every person with a disability and their family members, and I apologize to all, but if you believe, as I do, that homosexuals are born gay, and if you believe that they are socially and romantically handicapped, then it is hard to argue that homosexuality is not a disability."

Anne-Marie Oomen, his creative writing teacher at Interlochen, echoed this. "The word 'disability' is perhaps an odd choice," she said. "But when young people are coming out, it feels a bit like that otherness."

And yet Baumbusch has not directly addressed homosexuality in his writing. Rather, he prefers to universalize the pressures gay people face. Citing Oscar Wilde as a model, he said, "I would rather write about straight characters in gay conflicts than write plots with gay characters that will alienate a dismissive audience."

Often, he added, "people don't realize that people in my plays are gay characters with straight characters superimposed on them -- they're Trojan horse gay characters." Interjecting what might be perfect ad copy for his plays, he added, "You cry with them, you love them, you hate them, and you still think they're straight."

If that sounds precocious, his mother, Cherry, long ago got used to grown-up words flowing from the mouth of her babe. "When he was 21/2 years old, we were in the doctor's office waiting for his brother to be seen, and there was some adult who heard Paul discussing something," she recalled. "Paul was giving his opinion, and the man said, 'Well, he's 4 years old,' and Paul said, 'No, I'm 21/2,' and the man turned to me and said, 'You'll send him to a very special school.' "

Nor is his family immune to his pen. His play "Soccer Moms" is based on a group of mothers Cherry Baumbusch meets with regularly. "Everything is fodder for this boy," she said, laughing.

His plays' affluent suburban settings are another nod to his autobiography. "The suburbs are the best subject," he said.

And so it came to pass that a group of fictional suburbanites stood in an imaginary back yard at the Kennedy Center, trading barbs about carpooling while pointedly ignoring their lives' darker undercurrents. Taking a break, the actors ruminated about the title -- taken from "A Midsummer Night's Dream -- and expressed relief that the play did not have a "Hallmark ending."

"It doesn't tie up," said Lakeisha Raquel Harrison, who plays a neighbor attending the autistic boy's birthday party. "It leaves you enough to want more. When plays don't necessarily end nicely, it leaves you thinking."

For information, visit www.vsarts.org.

Paul Baumbusch's award-winning play "The Changeling," about a family's struggle with autism, will be performed at the Kennedy Center on Oct. 4."The Changeling" cast includes Tony Simione, left, as Jeremy, Leah Pike as Amanda, Lakeisha Raquel Harrison as Carla, Christine Reinhardt as Karen, and Emily Porter as Jo-Anne. The play is to be performed Oct. 4 at the Kennedy Center.