For decades, autism was believed to overwhelmingly affect boys. Yet a big new study out of Sweden provides perhaps the best evidence yet that girls aren’t less likely to be autistic — they’re just less likely to be diagnosed young.
Researchers looked across 35 years of health records for nearly 2.8 million people (an incredibly complete window into their lives thanks to Sweden’s universal health care system). They found that whether it was 2025 or 1995, boys under 10 were three to four times more likely to be diagnosed with autism than girls. But by adulthood, the gap had nearly disappeared.
The study might have looked at kids in Sweden, but it points to a global problem: Too many autistic girls are being missed during childhood.
That’s a critical time when social supports and interventions could help them learn to more easily navigate their world. On a more basic level, going unidentified means they are left until adolescence or even adulthood without a fundamental understanding of themselves.
Why do so many autistic girls fly under the radar? Child psychologists have a few theories. For starters, some of the traits of autism are expressed differently in girls than in boys. They often are milder — for example, girls with autism are more likely to hold eye contact and have an easier time with communication.
And although they may express strong interests, they tend to line up with things neurotypical girls are drawn to — say, Taylor Swift or makeup or animals, explains Conner Black, associate director of the Child Mind Institute’s Autism Center.
Those subtle differences make autistic traits easy to miss, even by pediatricians and therapists. That’s in part because girls don’t tend to display some of the big externalizing behaviors, like aggression or tantrums, that people tend to associate with autism in boys, Black says.
In recent years, experts have particularly focused on girls’ ability to “mask” or “camouflage” their autism traits. More so than boys, the desire to blend in is strong in young girls, and might be even more powerful in autistic girls, says Gina Rippon, a British neurobiologist whose recent book, “The Lost Girls of Autism,” chronicles the ways science has overlooked girls with autism.
That can be exhausting and impossible to keep up full-time. Girls might not display challenging behaviors at school but still melt down the moment they get home, Black says. That mismatch was illustrated in a 2024 study that found striking differences between teachers and parents’ perceptions of autism traits — things like having trouble interpreting body language or understanding social mores. Teachers viewed boys as having significantly more traits than girls — and consistently said girls had fewer traits than their parents identified.
Camouflaging might allow girls to navigate the early elementary school years, when there’s a lot of predictability. But the tactic starts to fall apart around middle school. “All of a sudden, the whole social environment becomes much more complex, much more unpredictable, much more pressurized, particularly for adolescents,” Rippon says. “The scaffolding that they’ve kind of built up to protect themselves is no longer fit for purpose.”
As the social dynamics of middle school set in — surely every adult has vivid memories of those difficult years — autistic girls might start to struggle. That doesn’t necessarily mean their autism suddenly becomes apparent to caregivers and clinicians; rather, they might start to be diagnosed with other conditions, like ADHD, depression, anorexia or self-harm. Those diagnoses can mean more years where their autism is missed — one study found an ADHD diagnosis can delay an autism diagnosis by nearly three years on average.
That delay can subject girls to treatments for other conditions that, though intended to help, can make life harder. Conventional eating disorder interventions, for example, might not be appropriate for someone with autism, Rippon notes. That’s because for some, the driver for an eating disorder has less to do with body image and more to do with sensory hypersensitivity or the need for rigid eating rituals.
Too many girls are missing out on early supports that could help them navigate life — not to mention missing out on the opportunity to have a deeper understanding of who they are and how their brain works. As robust research like the study out of Sweden makes it increasingly clear that autism is nearly as common in girls as in boys, there’s so much work to do to better meet girls’ needs.
That starts with simply studying girls more. Despite growing recognition over the last decade or so that autistic girls deserve more time, attention and research dollars, there are still glaring knowledge gaps that need to be filled. A big one is developing better diagnostic tools to capture the subtle traits of autism in girls when they are young, especially when girls are camouflaging those traits.
Teachers could use more education, too, to recognize the less obvious traits that might be showing up in their classrooms. Parents, meanwhile, are in the best position to advocate for their child, and pediatricians, therapists and educators should do a better job listening when parents are describing what they’re seeing at home.
None of this is to suggest that boys don’t deserve less; it’s simply that girls shouldn’t be left to struggle. The goal should be to get to a place where every child has the support they need to live their happiest, healthiest life.
Lisa Jarvis is a Bloomberg Opinion columnist covering biotech, health care and the pharmaceutical industry. Previously, she was executive editor of Chemical & Engineering News.
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