For years, autism was thought to be much more common in boys than girls. A large new study from Sweden suggests that isn’t true. Researchers followed over 2.7 million people and found that by adulthood, autism rates in males and females are nearly the same.

The difference is when children are diagnosed. Boys are more often identified in early childhood, while many girls aren’t diagnosed until their teen years. Girls may mask their challenges, have strong early language skills, or be misunderstood as anxious or moody rather than autistic, especially as social demands increase during adolescence.

Why This Matters for Families

Later diagnosis can mean years of:

• Feeling misunderstood
• Increased anxiety or emotional exhaustion
• Missed supports at school
• Parents being told to “wait and see”

For many families, a diagnosis later in childhood or adolescence brings both relief and grief, relief in finally having answers, and grief for the support that could have come sooner.

What Experts are Saying

Much of the expert commentary on this study suggests that the narrowing gender gap is largely due to increased identification of girls with milder autism presentations, while severe autism, which is more obvious early in development, remains more commonly diagnosed in boys.

What Parents Can Take Away

• Trust your instincts. If something doesn’t feel right, it’s worth asking more questions.
• Autism can look different in girls. Quiet struggles count.
• Late diagnosis does not mean late need. Support is helpful at any age.
• Your child is not failing. Often, the system simply didn’t recognize them early.

For parents, the takeaway is important: girls are not less autistic, they are often recognized later. If you’ve had concerns that were dismissed or delayed, trust your instincts. Quiet struggles still matter, and support can make a difference at any age.

Study link: https://www.bmj.com/content/392/bmj-2025-084164