Gender and Autism: Differences and Discrepancies

It’s long been known that boys are diagnosed with autism at a higher rate than girls. What remains unknown is why. Does it simply occur less in females? Are girls underdiagnosed? Or is something else at play?

As the number of people diagnosed with autism spectrum disorder (ASD) continues to grow, researchers and clinicians have had greater opportunities to understand the differences between boys and girls in autism diagnosis, research and treatment. 

More Diagnoses Unveil Discrepancies

Currently, autism is believed to affect boys more often than girls at a 4:1 ratio. Gender prevalence in autism is far better understood than it was a decade or two ago. Yet, whether autism is actually more prevalent in boys than girls remains unclear.

Diagnostic criteria has expanded to a wide spectrum of individuals at an overall prevalence rate that has grown to 1 in 36, according to the CDC. The changing rate, coupled with changing ASD definitions, makes knowing what the overall prevalence should be in the first place tricky, notes Catalight Chief Clinical Officer Doreen Samelson, Ed.D., MSCP. Without that baseline, it’s hard to gauge whether any subgroups are under or over-diagnosed.

Greater awareness of autism, laws that mandate insurance coverage of treatment and expansion into differential diagnoses have led to an increase in diagnosis, as well. “Is autism over diagnosed? Although largely indirect and anecdotal, evidence for possible overdiagnosis nonetheless exists,” wrote the authors of a “Journal of Child Psychology and Psychiatry” editorial.

Autism in Males vs. Females

The skewed sex ratio has been acknowledged since autism was first recognized in the 1940s. In the years since, research into autism-associated genetic disorders that are more prevalent in or exclusive to boys has mounted and helped establish evidence for a sex-based relationship with autism.

For example, fragile X affects both boys and girls, but males are more frequently affected, and with greater severity. Also, about 74 genes, out of 800 that are clinically known, relevant or susceptible to ASD were plotted on the X chromosome. Compared with similar sized chromosomes, X has a 50% higher ASD gene frequency, which supports the 4:1 male-female ratio.

The difference may also be because of diagnostic processes and disorder definition. The diagnostic process has been noted to be potentially more “boy-centric,” with current assessment practices not optimized for girls, according to 2021’s “Global prevalence of autism: A systematic review update.”

Several additional factors may be contributing to lower diagnosis rates in females. For one thing, girls may be more likely to “camouflage” autistic behavior than boys. Researchers have discovered that, as adults, females will continue this pattern of hiding autistic behavior by imitating others around them.

That may lead to delayed diagnosis or misdiagnosis, particularly in girls who do not have intellectual disability or who have lower support needs. Failure to get early intervention has many repercussions for optimal development, including greater likelihood of mental health or social struggles.

Autism and Gender Identity

Just like autism, gender identity is on a spectrum. Catalight clinicians have found more individuals are likely to identify as non-binary than individuals without ASD. That’s in keeping with other recent research. As diagnoses have grown, researchers have had more opportunity to do large-scale studies on experiences of people with autism.

A major study at the University of Cambridge found that autistic adults and adolescents are approximately eight times more likely to identify as asexual and ‘other’ sexuality than their non-autistic peers. It also found that there were differences in sexual orientation between the sexes. For example, autistic males are 3.5 times more likely to identify as bisexual than non-autistic males, whereas autistic females are three times more likely to identify as homosexual than non-autistic females.

Much Left to Learn

In recent years, clinicians and researchers are also discovering intriguing new patterns and questions about autism, sex and gender identity. And though autism is better understood than even a decade ago, there is still a great deal to learn about it, what its overall prevalence should be and subsequently what the “right” prevalence rate is by sex. And researchers are just beginning to explore questions of autism and gender identity.

Knowing the many complex factors behind autism and sex, and patterns with sexuality and gender identity in the ASD population is key in righting disparities in health equity. Awareness can help the community and the industry approach research endeavors and clinical interventions with greater caution, care and precision while fostering an accepting, inclusive environment.