Why More Girls Are Getting Autism Diagnoses Right Now

If you have been watching autism headlines and wondering whether the numbers are “exploding,” a new study from Saint Louis University and SSM Health has a calmer answer. In one large Midwestern health system, new autism diagnoses among boys and men stayed flat or went down from 2016 to 2024. New diagnoses among girls and women rose sharply after 2020 — and the researchers call that catch-up identification, not a sudden epidemic.

That matters at the kitchen table if you have a daughter who was waved off for years, or if you are an autistic woman who only got language for yourself as an adult. More girls are finally being counted. Many are still counted late.

What the study actually measured

The paper sits in JAMA Network Open (July 2026). Lead author Erick Messias, M.D., Ph.D., and colleagues looked at electronic health records for 171,134 patients who stayed connected to care — at least one clinical visit each year from 2016 through 2024 — inside a Midwestern system whose data warehouse covers patients across Illinois, Missouri, Oklahoma, and Wisconsin.

This is not a national CDC prevalence report. It is one health systems first-diagnosis pattern, tracked the same way before and after the pandemic years. That limit is useful. It keeps the claim honest.

Inside that cohort, females received an autism diagnosis an average of 3.4 years later than males — mean age 15.7 versus 12.3. Messias’s line, published with SSM Health, is plain: late diagnosis means years of missed support, accommodations, and self-understanding during the years when school, friends, and identity shift the hardest.

After 2020, female incidence rose about 19 percent per year overall. The climb was steepest for adolescent girls (about 22 percent per year from 2020 to 2024) and for younger girls (about 17 percent per year since 2020). Male incidence, across children, teens, and adults, stayed stable or declined.

One careful note on adults: the adult female increase in this dataset was positive but not statistically significant. So say “suggestive, not “proven,” for adult women in this paper. The clearer signal is in girls and teens.

What “catch-up” means in plain English

For a long time, autism tools and clinic habits were built mostly around how autism looked in boys. Girls who masked, scripted, or got labeled only with anxiety, eating trouble, or shy” often waited. When clinics start seeing those presentations earlier, the count of new diagnoses can jump even if the true number of autistic people in the population did not suddenly double.

That is the authors’ takeaway, restated for parents: the post-2020 rise in first diagnoses in this system looks like better recognition of autistic females, not a uniform population-level surge.

Saint Louis University’s Aug 31 summary says the same thing out loud — increased recognition, not epidemic. You can hold that sentence without denying anyone’s real support needs. A late diagnosis is still a late diagnosis. A child who needs speech, sensory planning, or a quieter lunch still needs those things whether the chart caught up this year or five years ago.

Old “Asperger” labels also kept fading from the records, which matches the diagnostic manual change from 2013. That is paperwork catching up to how clinicians already write charts. It is not a separate disease vanishing.

What this does not settle

One health system cannot tell you the autism rate on every playground in America. It cannot prove under-diagnosis is finished. The 3.4-year average delay is still sitting there in the same paper that shows girls diagnoses rising.

It also does not replace a careful evaluation. A rising diagnosis count is not a coupon for a five-minute telehealth label, and it is not a reason to skip listening to the person in front of you — autistic girls, autistic women, and nonbinary people who were missed under boy-shaped checklists.

If your household already uses Autism Digest’s Womens Autism checklist piece, keep it. This article is the news peg beside it: new data on who is being identified now, and how late.

What you can do this week

Keep the ask concrete. You do not need a statistics seminar to use this study.

• If a clinician says “girls don’t usually present that way,” you can answer: recent research in a large U.S. health system found girls’ new autism diagnoses rising after 2020 while boys’ stayed flat or fell — and girls were still diagnosed years later on average.

  
  

• Ask for an evaluator who has real experience with autistic girls and women, including masking, sensory history, and burnout — not only eye contact and playground notes.

  
  

• Write down the supports that already help at home and school (headphones, plain instructions, predictable transitions, AAC, quiet space). Bring that list to the appointment so the visit is about access, not proving you are “autistic enough.”

  
  

• If you are an autistic adult still hunting language for yourself, treat a careful adult evaluation as information, not a personality contest. The adult female trend in this paper was weaker statistically — that does not erase adult women who were missed.

  
  

• Save the DOI and the SLU summary. When someone waves a panic headline at you, you can hand back a citation instead of a vibe.

Subscribe to Autism Digest when you want the next diagnosis-news story counted in plain language. We will cite the page, not the panic.

Sources

Messias E, Casanova E, Huang R, et al. “Autism Spectrum Disorder Incidence by Age and Sex in a US Health Care System, 2016 to 2024.” JAMA Network Open. 2026;9(7):e2624561. https://doi.org/10.1001/jamanetworkopen.2026.24561

Autism Diagnoses Rising Fastest Among Girls and Women, According to New JAMA Research,” Saint Louis University News, August 31, 2026. https://www.slu.edu/news/2026/august/autism-diagnosis-rising-jama-research.php

“SSM Health physician leads autism study published by the AMA,” SSM Health, summarizing Messias et al. https://www.ssmhealth.com/newsroom/blogs/ssm-health-matters/july-2026/ssm-health-physician-leads-autism-study-published-by-the-ama