Misty Copeland is the most famous ballerina in America, and she's black.

In 2016, this shouldn't be such an outrageous idea. But while it's rare for any child dreaming of sugar plums to become a professional ballet dancer, it's almost impossible for a dancer of color. Especially if she's female.

Director/producer Frances McElroy, based in Narberth, points this out in Black Ballerina, a eye-opening documentary that will be shown 9 p.m. Monday on WHYY and other PBS stations. While one voiceover describes ballet as being "like singing with your body," another notes that "mainly it's a white world."

Think rows of sylphs, snowflakes, and shades, slips of powdery white dancers fluttering across the stage.

Why must they be white?

Many company directors - consciously or not - think, "I don't know if it looks like ballet if it doesn't look like 12 identical swans," says Virginia Johnson, artistic director of the primarily black Dance Theatre of Harlem, in Black Ballerina.

This skepticism is aimed toward both color and body shape. The typical Balanchine image of the ballerina - which has informed companies around the United States - is that of a woman with a small head, long legs, and a very slim body. Black dancers often have more muscular builds.

While this ideal is imprinted throughout the ballet world, European companies and audiences have been more accepting of dancers of various looks.

BLACK BALLERINA Trailer from Shirley Road Productions on Vimeo.

Raven Wilkinson, who was perhaps the first successful black ballerina, landed a job in the 1950s with Ballet Russe de Monte Carlo, a premier company that toured the United States. But she had to leave a tour when they and a Ku Klux Klan convention landed in Montgomery, Ala., at the same time. She eventually left the company, stopped dancing for a while, and then joined the Dutch National Ballet, where she found success. But she also missed the United States. After returning home, she never danced again.

Black Ballerina has many Philadelphia references, with interviews from Pennsylvania Ballet artistic director emeritus Roy Kaiser, to Philadanco founder Joan Myers Brown, to a former University of the Arts student who had so little luck with auditions that she eventually became a flight attendant instead.

Another former ballerina in the film, Delores Browne, has taught at Philadanco and Alvin Ailey. She fell in love with ballet as child, and she and her friend went from school to school looking for classes. Browne didn't find out until later that she was turned away from all the Philadelphia ballet schools in which her mother tried to enroll her. Instead, she joined a ballet club in high school, and later was accepted into the prestigious School of American Ballet in New York. From there, she joined a company with other black dancers.

"They changed our name from Ballet Americana to New York Negro Ballet, because they wanted audiences to think we were exotic," Browne says.

The New York Negro Ballet toured Europe and danced a lot of modern pieces. But they also performed very classical works. "Nobody ran screaming out of the theater," Browne says. "It was wonderful, warm applause and acceptance."

Black Ballerina includes many clips of Pennsylvania Ballet, and fans will enjoy spotting favorite dancers. Jermel Johnson is pointed out as the rare black ballet dancer, and the film notes that men have always had an easier time than women.

While dancers and company directors in the film say it's extremely difficult for black dancers to get a job in a ballet company - especially if that company already has a "token" black ballerina - they acknowledge that the task of diversifying dance troupes is made more difficult by social attitudes besides racial division.

Many parents are more interested in activities that will lead to a high income rather than the arts, says Ashley Murphy, a dancer in Dance Theatre of Harlem. She reluctantly went to college at her parents' persistence but left after two weeks because she really wanted to dance.

"They will always tell you to go out for the NFL, because it will make you a million dollars," Murphy said of parents like her own. "They're not going to say, 'Go be a ballerina and struggle all your life.' "

Lack of opportunities beget lack of interest for black dancers, adds Philadanco's Brown. "I think if they saw more of themselves on stage, more in ballet companies, more on television, doing just that, they would be encouraged. But I think they get deterred by the lack of opportunity."

More than 50 years after the civil-rights movement of the 1960s, ballet is diversifying - ever so slowly. In 2013, American Ballet Theatre, where Misty Copeland dances, set up Project Plie, a program to train and support more students of color.

The Charlotte Ballet, as artistic director Jean-Pierre Bonnefoux notes in Black Ballerina, has a partnership with Dance Theatre of Harlem and accepts two students every year into the North Carolina troupe's second company.

And this season, Jermel Johnson is joined at Pennsylvania Ballet by two black women: Nayara Lopes, a corps dancer; and Nardia Boodoo, an apprentice.

Perhaps someday Black Ballerina will be seen as a documentary reflecting a bygone moment. Until then, it speaks very much for the present and is worth watching.