Why Are More Males Diagnosed with Autism? Breaking Down the Gender Differences

Overview: This article explains the systemic and biological reasons why males have a higher frequency of autism than females and the differences in autism symptoms between the two. 


* Please note that this article explores the general differences in autism symptoms between genders. These patterns are in no way absolute. The terms “male” and “female” in this article are used to identify people who were assigned those genders at birth and who still identify with that gender later in life. This article does not discuss gender fluidity or trans issues in the autistic community – for more on those issues, please see the article on gender identity and sexuality.*

Females have historically been diagnosed with autism at a significantly lower rate than males. The most recent CDC analysis documents that about 1% of people who were assigned female at birth (AFAB) were diagnosed with autism, while about 4% of people who were assigned male at birth (AMAB) were diagnosed with autism (Maenner et al., 2020). Research regarding the differences amongst genders found that although there is assessment bias in these numbers, there are also genuine differences in the causes of autism and the ways that the condition presents between AFAB and AMAB individuals.

Why More Males?

The 4:1 ratio of male to female occurrence of autism is likely due to many factors, some of which are genetic. Recent studies have identified hundreds of genes that can contribute to the development of autism (refer to the “Causes of Autism” article for more), including male-specific genes, female-specific genes, and shared genes. Dr. Yi Zhang and colleagues (2020) found that these genes are often co-expressed in a protective manner in females which leads to what is known as the “female-protective effect” that helps to stave off autism. They also posit that this genetic variation may contribute to the different presentations of male and female autism. The researchers acknowledge, however, that gender based genetic differences do not account for the large disparity in diagnosis between male and female autism.

The systems that diagnose and treat autism likely contribute to the autism gender disparity. It has been demonstrated that questions on common autism assessments such as the Autism Quotient (AQ) or the Implicit Association Test (IAT) are biased towards male autistic traits and are less likely to catch female autistic traits (Brickhill et al., 2023). Sadly, this standardization of autism traits as “male” means that there many potential autism diagnoses for females have been missed. The large ranks of undiagnosed autistic females have led to what researchers have termed the “lost generation” of autistic women (Lai, Baron-Cohen, 2015). These are mostly older women who were likely to be misdiagnosed with a host of other disorders when they were in fact on the autism spectrum and needed support for that condition. Dr. Lai (2017) has found that diagnoses for women have been increasing, but women are still frequently unrecognized and underrepresented in the autism community.

Gender Differences in Autism

Assessment bias is not the only factor that contributes to the underdiagnosing of females. Research shows that “female autism” often looks different than “male autism.” Females on the spectrum often show more nuanced and subtle symptoms that may be harder for clinicians to identify. Women also tend to be better at “camouflaging” or “masking” their autism traits so that they are not as obvious in social situations or assessments (Brown et al., 2020). This masking requires robust attention to social situations and consistent effort to utilize learned social “scripts.” Using a script is akin to acting out the lines in a play. Like acting, scripts are practiced imitations of social situations that autistic individuals use to better fit-in and connect with others. It appears that females tend to learn and practice these scripts significantly better than autistic males (Simcoe et al., 2023). While this practice can make an autistic women’s social symptoms appear less cumbersome, the reality is that they must work exponentially harder than their non-autistic peers to achieve the same social results. Studies have shown that up to 90% of autistic women report masking in this manner (Cassidy et al., 2018). The women further report that masking behaviors are exhausting to maintain over longer periods of time. This exhaustion may exacerbate mental health struggles like anxiety and depression which may then result in those issues being the focus of mental health treatment and support instead of the underlying autism.

Gender differences in autism symptoms goes beyond socialization. Another frequent difference is found in the object of a person’s restricted interests, with autistic females tending to focus on more socially acceptable activities than males (Edwards et al., 2024). For example, many young girls love horses, so when an autistic girl becomes fixated on all things equine, that behavior may not be considered abnormal and thus may go unnoticed. The same is true for common interests at most every stage of a female’s life – whether it be fashion in high school, politics in college, or animals at any age. Given that those passions are more typical for the non-autistic population, when an autistic girl is overly focused on the activity the behavior is less likely to be recognized as a symptom of autism.

Alternatively, females on the spectrum are more likely to struggle with hyper or hyposensitivity than males on the spectrum (Ormund et al., 2018). These sensitivities generally manifest as an aversion to the feel of certain clothing fabrics, smells, and/or noises. The aversions, while often quickly identified as autism symptoms in males, are equally often dismissed when observed in females, instead labeling the female as “sensitive” or “picky” instead of potentially being on the autism spectrum.

Similarities Between Genders

While there are glaring differences in autism symptoms between genders, there are also a tremendous number of similarities. Most autistic individuals, regardless of gender, tend to have similar levels of cognitive rigidity, repetitive behaviors, and emotion dysregulation. They also have similar levels of social drive and desire to participate in the world and are often more alike than different.

Conclusion

Although historical studies on Autism suffer from some of the same male-normativity that is found in most medical research, there is a growing understanding of the important gender differences in the autistic population. Females tend to appear more socially capable, have more socially acceptable restricted interests, and more sensory sensitivities than males. While these are generalized factors, they are critical to assessing, treating, and understanding any individual on the spectrum.

References

Brickhill, R., Atherton, G., Piovesan, A., & Cross, L. (2023). Autism, thy name is man: Exploring implicit and explicit gender bias in autism perceptions. PLoS One, 18(8), e0284013.

Brown, C. M., Attwood, T., Garnett, M., & Stokes, M. A. (2020). Am I autistic? Utility of the girls questionnaire for autism spectrum condition as an autism assessment in adult women. Autism in Adulthood, 2(3), 216-226.

Cassidy S, Bradley L, Shaw R, Baron-Cohen S. (2018). Risk markers for suicidality in autistic adults. Mol Autism. 9 (1):42.

Edwards, H., Wright, S., Sargeant, C., Cortese, S., & Wood‐Downie, H. (2024). Research Review: A systematic review and meta‐analysis of sex differences in narrow constructs of restricted and repetitive behaviours and interests in autistic children, adolescents, and adults. Journal of Child Psychology and Psychiatry, 65(1), 4-17.

Lai MC, Baron-Cohen S. (2015). Identifying the lost generation of adults with autism spectrum conditions. Lancet Psychiatry;2(11):1013–1027.

Lai MC, Lombardo MV, Ruigrok AN, et al.. (2017). Quantifying and exploring camouflaging in men and women with autism. Autism. ;21(6):690–702.

Maenner MJ, Warren Z, Williams AR, et al. Prevalence and Characteristics of Autism Spectrum Disorder Among Children Aged 8 Years — Autism and Developmental Disabilities Monitoring Network, 11 Sites, United States, 2020. MMWR Surveill Summ 2023;72(No. SS-2):1–14.


Ormond S, Brownlow C, Garnett MS, Rynkiewicz A, Attwood T. (2018) Profiling autism symptomatology: An exploration of the Q-ASC parental report scale in capturing sex differences in autism. J Autism Dev Disord;48(2):389–403.

Simcoe, S. M., Gilmour, J., Garnett, M. S., Attwood, T., Donovan, C., & Kelly, A. B. (2023). Are there gender-based variations in the presentation of Autism amongst female and male children?. Journal of autism and developmental disorders, 53(9), 3627-3635.

Zhang, Y., Li, N., Li, C., Zhang, Z., Teng, H., Wang, Y., ... & Sun, Z. (2020). Genetic evidence of gender difference in autism spectrum disorder supports the female-protective effect. Translational psychiatry, 10(1), 4.