Sixteen-year-old Swedish activist Greta Thunberg is the symbol of a climate change generation gap, a girl rebuking adults for their inaction in preventing a future apocalypse. Thunberg’s riveting speech at the UN's Climate Action Summit has been viewed more than 2 million times on YouTube, and she was considered a viable contender for the Nobel Peace Prize.

In a tweet, Thunberg explained what made her so fearless: “I have Aspergers and that means I’m sometimes a bit different from the norm. And—given the right circumstances—being different is a superpower. #aspiepower.”

People with Asperger’s applaud the way she reframed a “disorder,” as it used to be called in the Diagnostic and Statistical Manual of Mental Disorders, into an asset. But Thunberg’s comments also fuel a lingering debate about whether Asperger’s even exists as a distinct condition—and if it doesn’t, why people are still so attached to the designation.

Asperger syndrome, first coined in 1981, describes people who have problems with social interaction, repetitive behaviors, and an intense focus on singular interests. Sheldon Cooper, the theoretical physicist on the long-running TV show “The Big Bang Theory,” became an exaggerated prototype, a brilliant person who missed social cues and couldn’t grasp irony.

His awkwardness spawned humorous predicaments, but in real life, people with Asperger’s can face more daunting challenges. It became a diagnosis in 1994, distinct from autistic disorder, but the lines were blurry even then. In 2013, the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (known as DSM-5) eliminated Asperger’s and redefined the autism spectrum as encompassing level 1 (“requiring support”) to level 3 (“requiring very substantial support”).

“Technically, the DSM-5 essentially made Asperger’s a non-diagnosis,” says Dania Jekel, executive director of the Asperger/Autism Network, which formed after Asperger’s first gained official status, from an outpouring of people seeking resources and a sense of community.

The World Health Organization also is eliminating Asperger syndrome from its International Classification of Diseases. The ICD-11, which was adopted this year and will be implemented globally by 2022, instead calls it “autism spectrum disorder without disorder of intellectual development and with mild or no impairment of functional language.” Proponents of the change hope to reduce stereotypes. For example, girls were much less likely to receive an Asperger’s diagnosis than boys, and girls were more likely to be diagnosed at an older age—a disparity that points to bias. Meanwhile, placing people “on the spectrum” equalizes access to resources, including insurance coverage.

“The diagnosis of Asperger’s enabled the creation of a large and very supportive community and allowed people to find relevant resources. Changes in DSM-5 jeopardized that.” Dania Jekel

But Jekel worries that some people with Asperger's-like attributes will return to the ambiguous space they once occupied—too well-functioning to be diagnosed on the autism spectrum, but still in need of significant support. “Twenty-two years ago, there was a whole group of people who were unidentified, had no resources, didn’t know each other,” she says. “The diagnosis of Asperger’s enabled the creation of a large and very supportive community and allowed people to find relevant resources. Changes in DSM-5 jeopardized that.”

Erika Schwarz, for example, wasn’t diagnosed until she was 39. Asperger’s explained a lot about her struggles in the workplace and with personal relationships. It made her wonder how different her life might have been if she had known—and had help learning how to cope. “It does give you a space to have a bit of compassion for yourself,” she says.

When she watches Thunberg on the world stage, she remembers herself as a young girl, intensely concerned about environmental degradation. “All the things I worried about as a kid, they’re validated,” says Schwarz, 50, who is now an environmental artist.

Yet Thunberg’s rise to icon status has also stirred long-standing resentments about how people view the rungs of the spectrum. The levels in the current DSM definition of autism are based on support needs, which can be fluid. “I would put myself at all three levels, inconsistently,” says Terra Vance, founder and chief editor of the online publication the Aspergian. But the levels also can feel like a ranking: more impaired or less so.