A gymnasium full of students sat quietly on the floor at Laurel School in Atherton on March 3, or as quietly as a roomful of students can sit, as on stage young adult actors playing 10-year-olds put on a play about putting on a play.

There were plenty of lines that made the students laugh or cheer, and some aimed squarely at the adults in the room, but the underlying theme of "Oskar and the Countless Costume Changes" was a serious one: gender roles and identity. The plot involved Oskar, who was in charge of his school's play, but couldn't bring himself to let Frank play the princess and Beth play the knight, as they requested.

"Boys are boys, and girls are girls," says Oskar.

But Beth can't figure out how to sound the way Oskar thinks a princess should sound, and Frank shudders at the thought of playing a fierce dragon and fighting the knight, played by Oskar. They're all uncomfortable in their assigned costumes, but gamely try to do what they've been asked.

In the end, though, after a nightmare in which his play bombed, Oskar has a change of heart and lets everyone take the roles they're longing for. The play gets a rave review in the student newspaper.

"None of this would have been possible without my amazing costars, Beth and Frank," says Oskar. "They taught me that sometimes the best boy for the job is a girl and sometimes the best girl for the job is a boy. They are not only my best friends. They are also my heroes."

Afterward, when the actors asked the students about what had happened in the play, Adrian, a third-grader at Laurel, was ready with an answer. Oskar, he said, "made them play parts that were what your gender was. But actually, it's your soul that you play."

Later, third-grader James wrote a review of the play as an in-class writing assignment. "At this assembly your kids learned that no matter what gender you are you can do anything you want to do. We were laughing a lot when it was going on and we really liked the play. Nothing like swear words were said, but there were funny sounds that we enjoyed a lot. Ask your kids about what they saw and hopefully they will say something positive about the ... great actors who performed the play we watched."

That review would probably bring a smile to the face of Amy Cole-Farrell, director of education for TheatreWorks Silicon Valley, and director of the play. Since 2007, she said, TheatreWorks has been doing plays with Oskar in the central role in collaboration with the Palo Alto Unified School District since 2007. The Oskar plays have serious themes such as bullying or stress, but also "the same fun feeling to them," she said.

Since a new play hadn't been added to the repertoire in five years, Prince Gomolvilas, who had also written the previous Oskar plays, wrote this one, in collaboration with Matt Ackels.

The topic was chosen, Ms. Cole-Farrell said, by "looking at what was going on in the schools and what was being talked about nationally."

A staged version of an early version of the play was done for parents and administrators, and the Gender Spectrum organization gave feedback. A staged reading was done for students before the script was finalized.

While the plays have been commissioned in cooperation with the Palo Alto school district, the program "was always intended to go beyond the Palo Alto schools," said Ms. Cole-Farrell. TheatreWorks actors perform for schools in cities ranging from San Rafael to Gilroy, and in the East Bay.

A study guide for parents and teachers is distributed to the schools where the play is performed.

Laurel has Oskar plays each year, said Laurel counselor Ashley Guilliot. "I'm so glad TheatreWorks took on this subject because I feel so many organizations and people want to shy away from it, or believe elementary school students are too young for this subject matter," Ms. Guilliot said.

"The truth is this topic is relevant to everyone, including children," she said. "All children have different interests and abilities; oftentimes they don't fit into traditional gender roles and that can lead to children feeling like something is wrong with them. It can also lead to bullying and discrimination when gender roles and gender identity isn't discussed. Ignoring the topic doesn't help anyone."

Ms. Guilliot said seeing the play "was also reassuring for students who don't fit into the traditional or stereotypical gender roles to see that they aren't alone and there is nothing wrong with their interests."

Ms. Cole-Farrell said TheatreWorks still has room to add a few more schools to its schedule.

TheatreWorks' website has more information.