A 10-year-old girl has delivered a heartfelt plea and a great opportunity to Mattel (MAT -0.66%). American Girl fan Melissa Shang, with the help of her older sister, posted a short and sweet YouTube video and Change.org petition last week asking Mattel to make a Girl of the Year doll with a disability. Shang, who uses a wheelchair because she has a form of muscular dystrophy, says her request fits with the American Girls theme of dealing with challenges.

"I don't want to be invisible or a side character that the main American Girl has to help. I want other girls to know what it's like to be me, through a disabled American Girl's story," Shang wrote in her petition. "American Girls are supposed to represent all the girls that make up American history, past and present. That includes disabled girls."

Her video and petition are gaining traction on YouTube and Twitter, in the media, and with Rookie, a popular website for teen girls. All this attention presents a great opportunity for one of Mattel's biggest brands.

All-American phenomenon

For parents of tween girls, the American Girl craze needs no explanation. For the rest of us, the salient facts are that the 27-year-old doll line has a big, loyal customer base and is a darling of the media. ABC's Good Morning America turned over a good chunk of its Dec. 31 show to an exclusive preview of the 2014 American Girl of the Year doll, a blonde dance student named Isabelle Palmer, which went on sale the following day.

American Girl dolls are popular with parents and teachers, too. Mattel's other popular doll brand, Barbie, has drawn criticism over the years for its depiction of the female form. But American Girl dolls are preadolescent and hail from real times and places, including pre-Independence Nez Perce lands, the Civil War-era South, and turn of the 20th century New York City. Girl of the Year dolls represent modern girls with a variety of backgrounds and interests.

In the doll world, American Girl towers over the landscape, with the biggest consumer toy catalog in the U.S. -- nearly half a million American Girl magazine subscribers, 23 million dolls, and more than 140 million books sold to date, and an ever-expanding roster of huge American Girl destination stores where girls can shop for themselves and their dolls, relax in the salon, have lunch with friends, and host birthday parties. Mattel reported that for the third quarter of 2013, global American Girl sales rose 20%. (Barbie sales, for comparison, rose 3%.)

Diversity delivers goodwill

Because Shang makes the point that disabled girls, like American Girl story characters, face and overcome obstacles, a disabled Girl of the Year seems like a logical move. And because the American Girl line includes diverse ethnicities, a Girl of the Year in a wheelchair seems like a logical extension of the brand's inclusive appeal.

Other companies have gained good press by using diverse models, like the new catalog from U.K. clothing chain Debenham's that features models of all ages and sizes, including amputees with and without prosthetic limbs, rocking the latest looks.

Wet Seal (NASDAQ: WTSL) earned raves last year in the press and the disability community for its ads featuring 17-year-old Karrie Brown, an aspiring model who has Down syndrome. Target (TGT 1.03%) and Nordstrom (JWN 0.96%) both featured a 6-year-old with Down syndrome named Ryan in their catalogs without any fanfare, but shoppers and parents noticed and appreciated it.

These are positive steps, but the fact is that they're noteworthy because they're uncommon. With almost 20% of the American population having some sort of disability, according to census data, representation of the disabled in the media, toys, and games has a long way to go.

Reflecting reality

The number of U.S. kids who use wheelchairs is relatively small; census data puts the total number of U.S. wheelchair users living outside institutions at about 4 million. But thanks to ADA and modern educational mainstreaming, this generation of kids has grown up with more inclusion of and access for the disabled than previous generations.

A place in the Girl of the Year lineup would be a big validation for disabled tween girls and a feather in Mattel's cap. Even if most of American Girl's target market is able-bodied, they probably attend school with wheelchair users or see them out and about in their communities. A Girl of the Year doll and book that highlight those challenges -- along with how much disabled girls have in common with their able friends -- would be right in line with the American Girl ethos and with the modern American experience.