Autism is diagnosed at a 4:1 boys to girls ratio. Several factors may account for the underdiagnosis or missed diagnosis in girls.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that presents social challenges for individuals.

There isn’t one specific test to diagnose autism, and because of this, some people aren’t diagnosed correctly, or the diagnosis may be missed. Autistic people may have varying abilities, with some needing high levels of support and others needing little help.

There are differences in how autism is diagnosed. It may be more often missed in females due to current diagnostic criteria. Females may be diagnosed later in life due to bias, less obvious symptoms, and genetics.

Language matters

Sex and gender exist on a spectrum. We use “male” and “female” in this article to reflect the terms assigned at birth. However, gender is solely about how you identify yourself, independent of your physical body.

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Autism is more common in boys than girls. A 2018 study notes that autism is identified in females less than in males.

Epidemiological studies estimate a 4:1 male-to-female ratio, showing that females may be missed and underdiagnosed.

Autism is more common in males than females because it shows up differently in boys and girls.

According to a 2022 literature review, there are more similarities that exist in early childhood between males and females than differences.

Findings indicate that factors, such as age of diagnosis and intellectual functioning, can lead to varying results in the differences between autism in boys vs. girls.

This also contributes to categories where the presentation of autism differs between females and males, such as:

Social communication

The literature review mentioned above examined social communication differences in autism and found that autistic girls were more likely to have an advanced vocabulary than autistic boys.

They also found that females were less likely to imitate their parents when compared to males’ imitation behavior.

The study also looked at non-verbal communication and friendship behaviors and found no differences in autistic males and females. The differences may account for why females are underdiagnosed, as the characteristics of autism may present differently.


Females tend to mask their autistic symptoms more than males. For example, research from 2019 indicates that females are more likely than males to camouflage their symptoms.

It suggests that females might have to display more intense or a higher number of symptoms to receive a diagnosis of autism.

Motor Skills

A large 2021 research indicates boys scored lower in motor skills than girls. Boys scored lower in manual dexterity and balance than girls at a preschool age.

Girls may present motor skills difficulties later in life, leading boys to receive an earlier diagnosis. The study did show that autistic children do develop fine motor skills differently than their neurotypical counterparts.

The Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-5-TR) lists the same symptoms for autism spectrum disorder in males and females.

According to the DSM-5-TR, the symptoms of autism spectrum disorder include:

  • persistent difficulties in social interactions
  • trouble with social-emotional reciprocity
  • deficits with non-verbal communication
  • challenges in developing, maintaining, and understanding relationships
  • repetitive interests and fixations
  • wanting things to be the same
  • repetitive motor movements
  • hypo or hyperreactivity to sensory input
  • strict adherence to routines

Since there are no known differences in the symptoms between males and females in the DSM-5-TR, other theories account for the differences in diagnosis between males and females. One 2020 review proposes two theories of why autism is diagnosed more in females than males.

The first theory is known as the female protective effect theory. This theory suggests that females have more environmental and genetic factors that “protect” them from autistic characteristics, implying autistic females have more relatives with autistic traits and need to inherit more traits of autism to show characteristics of the condition as often as boys.

This area is further being researched, and limited evidence supports this theory.

The second theory is diagnostic bias in diagnosing autistic females. While the criteria for autism are the same in females and males, females may be less likely to be diagnosed or diagnosed later because the criteria for an autism diagnosis were based primarily on male behavior. But further research is needed to support this claim.

Boys are diagnosed with autism at a 4:1 ratio, more so than girls. Part of the reason may be that the criteria for autism are biased and based on the typical presentation of the disorder in boys.

Another reason is that girls mask their symptoms better, and boys present more intense, noticeable symptoms.

Knowing what signs to look for can help girls obtain a diagnosis quicker if needed for accommodation. Females are often diagnosed later in life; sometimes, a diagnosis can help everyone better understand certain behaviors.

If you’re autistic or believe that someone you care about is, you can find support and resources. Consider reaching out to a mental health professional near you for guidance. You can find mental health professionals in your area using the FindCare Tool.