Autism in girls has been historically underrecognized, but the gap between male and female diagnoses is closing fast. A large Danish birth-cohort study tracking trends over decades found that the male-to-female ratio for autism incidence dropped steadily with age at diagnosis, reaching just 1.2-to-1 by age 20 in 2022, and projections suggested the ratio would hit parity by 2024.1PubMed Central. Time trends in the male to female ratio for autism incidence: population based, prospectively collected, birth cohort study That shift does not reflect a sudden biological change. It reflects the field catching up with what was always there, as clinicians, researchers, and educators learn to recognize how autism can look different when the person experiencing it is female.
Why Girls Were Missed for So Long
Much of autism research from the 1940s through the early 2000s drew predominantly on male participants. The diagnostic criteria, the screening tools, and the clinical intuitions of professionals all developed around a profile that skewed male. One study found a significant implicit bias linking maleness with autistic traits, suggesting that the very concept of autism in many people’s minds defaults to a boy or man.2PubMed Central. Autism, thy name is man: Exploring implicit and explicit gender bias in autism perceptions That cultural association has real consequences at every stage of the identification pipeline.
The bias shows up in schools. An experimental study presented primary school educators with vignettes describing children with autistic characteristics. When the child in the vignette was female and showed a typically female autism profile, teachers were less likely to flag them as potentially autistic. Female gender reduced recognition specifically for the female phenotype, not for a classically male presentation.3PubMed. Recognition of Girls on the Autism Spectrum by Primary School Educators: An Experimental Study Not all studies replicate this finding cleanly; another experiment found that the child’s gender alone did not change whether teachers chose autism as a diagnosis.4Psychology in the Schools. Investigating the effects of perceived student gender on primary school teachers’ recognition of autism The discrepancy likely depends on whether the presentation described fits the “textbook” male profile or not. When the symptoms look like what teachers expect, gender matters less. When the symptoms are subtler or differently expressed, the girl gets overlooked.
The bias also shows up in the tools themselves. Analysis of the ADOS-2, the most widely used diagnostic observation instrument, found that the hand mannerisms item showed consistent measurement bias against female children across multiple modules. At the individual level, that kind of bias could lead to underestimation of autism severity in girls.5JAMA Network Open. Analysis of Race and Sex Bias in the Autism Diagnostic Observation Schedule (ADOS-2) And when both boys and girls are assessed on the ADOS-2, boys score higher on average on overall autism symptom severity, social affect, and repetitive behaviors, with a moderate effect size for overall score and social affect and a smaller one for repetitive behaviors.6PubMed Central. Sex Differences on the ADOS-2 Whether that gap reflects a genuine difference in trait severity or an instrument that was calibrated around boys remains a live question.
How Autism Tends to Present Differently in Girls
The differences are not about having or lacking core autistic traits. Girls on the spectrum still experience differences in social communication and repetitive or restricted behaviors. But the specifics tend to differ in ways that make the traits harder to spot.
Restricted interests offer a clear example. A systematic review found that autistic girls tend to have fewer restricted interests than boys, and the content of those interests is closer to what neurotypical girls also enjoy, which complicates screening.7PubMed. Characteristics of restricted interests in girls with ASD compared to boys: a systematic review of the literature A girl intensely fixated on horses, animals, or fictional characters may look unremarkable to a parent or teacher because those interests are common among girls generally. A study based on caregiver report confirmed that gender differences in special interest categories fell along typical gender lines, with more girls interested in animals and arts and crafts, and more boys interested in math and construction.8PubMed. More similar than different: Characterizing special interests in autistic boys and girls based on caregiver report The intensity and quality of the interest may be distinctly autistic, but its subject matter blends in.
Repetitive and restricted behavior patterns also differ in profile. Research on gender differences in these behaviors found that the items best discriminating girls from boys were compulsive behaviors, insistence on sameness, and self-injurious behavior, while boys scored higher on stereotyped movements and classically “restricted” interests.9PubMed. Gender differences in restricted and repetitive behaviors and interests in youth with autism A girl who insists on rigid routines around mealtimes, or who picks at her skin, or who becomes distressed by small changes in plans, is displaying repetitive and restricted behavior. But it is less visually obvious than hand-flapping or lining up objects.
Socially, autistic girls tend to show more motivation to connect with peers than autistic boys. Autistic girls in one study showed social motivation and friendship quality similar to neurotypical girls, whereas autistic boys reported both lower motivation and qualitatively different friendships. But there was an important catch: autistic girls reported high levels of relational aggression within their friendships, suggesting they struggle with identifying and managing conflict even when they desire social connection.10PubMed Central. Gender Differences in the Social Motivation and Friendship Experiences of Autistic and Non-autistic Adolescents A follow-up study echoed this: autistic girls’ friendships looked similar to neurotypical girls’ friendships in many ways, but involved significantly more conflict and more difficulty resolving it.11PubMed. ‘It’s different for girls’: Gender differences in the friendships and conflict of autistic and neurotypical adolescents
Sensory differences also appear to split along gender lines. Autistic girls show more severe atypical sensory responses than autistic boys, particularly in hearing and in balance and motion processing, a pattern that is the opposite of what is seen in neurotypical children, where boys tend to show slightly more sensory processing quirks.12PubMed Central. Sex differences in sensory processing in children with autism spectrum disorder Young adult women with autism also report higher sensory hypersensitivity, while men report higher hyposensitivity, suggesting a pattern where autistic women are more prone to being overwhelmed by sensory input and autistic men more prone to under-registering it.13Research in Autism Spectrum Disorders. Similar overall expression, but different profiles, of autistic traits, sensory processing, and mental health between young adult males and females
Masking and Camouflaging
One of the most discussed reasons autistic girls fly under the radar is masking, sometimes called camouflaging. This refers to the strategies autistic people use to suppress visible autistic traits and perform neurotypical social behavior. A systematic review found three consistent patterns across the research: people with more autistic traits report more camouflaging, sex and gender differences exist in camouflaging, and higher self-reported camouflaging is associated with worse mental health.14PubMed. Camouflaging in autism: A systematic review
A review of the broader literature concluded that camouflaging is more common among autistic women, who tend to be more self-aware of their autistic symptoms and develop self-control strategies around them.15PubMed Central. Camouflage and masking behavior in adult autism Qualitative research with autistic adolescent girls captures what this looks like in practice. Girls describe deliberately hiding their behaviors when others are watching, smiling and nodding during conversations they do not understand to avoid being laughed at, and sometimes changing their entire personality to fit in.16PubMed Central. “Camouflaging” by adolescent autistic girls who attend both mainstream and specialist resource classes: Perspectives of girls, their mothers and their educators These are not minor social adjustments. They are exhausting, sustained performances, often motivated by fear of bullying or exclusion.
Masking has a measurable effect on where autistic traits get noticed. A study on parent-teacher discrepancies found that being female predicted greater disagreement between parents and teachers on autism trait ratings, with parents rating higher and teachers rating lower. The gap widened with age.17PubMed Central. Sex Differences and Parent–Teacher Discrepancies in Reports of Autism Traits: Evidence for Camouflaging in a School Setting In other words, autistic girls hold it together at school and fall apart at home. That pattern is one of the most recognizable red flags for undiagnosed autism in girls, and it is the opposite of what prompts a typical school-based referral.
The cost is not just practical. Higher levels of masking predict more depression, more anxiety, lower self-esteem, less authentic living, and greater self-alienation.18PubMed Central. What You Are Hiding Could Be Hurting You: Autistic Masking in Relation to Mental Health, Interpersonal Trauma, Authenticity, and Self-Esteem Masking is not just hiding traits from the world. Over time, it means losing track of who you actually are.
The Female Protective Effect
The underdiagnosis of girls is not the whole explanation for why fewer females are diagnosed. There also appears to be a genuine biological difference in susceptibility. Researchers call it the female protective effect: females seem to require a higher genetic burden to develop autism, as if their biology provides a buffer that males lack.
The evidence for this is consistent across several types of genetic data. An early large-scale study found that autistic females carry significantly more large, rare, and gene-disrupting copy number variants than autistic males. The bigger and rarer the genetic change, and the more it overlapped with neurodevelopmental genes, the more pronounced the female excess became.19American Journal of Human Genetics. Greater Mutational Burden and Less Specificity in Autistic Girls A subsequent study confirmed that female patients with autism carry significantly more loss-of-function and damaging missense mutations than male patients, with an average differential of about 0.13 more damaging new mutations per person.20Translational Psychiatry. Genetic evidence of gender difference in autism spectrum disorder supports the female-protective effect
The effect extends to inherited risk as well. Under the female protective model, mothers should be able to carry more autism-related genetic risk than fathers before crossing the diagnostic threshold themselves. That is exactly what researchers found: mothers of children with autism carried significantly more polygenic risk for autism than fathers of children with autism.21PubMed Central. The female protective effect against autism spectrum disorder This means the same amount of genetic risk that produces autism in a boy may not produce it in a girl, and a mother can silently pass along risk she herself never expressed as a diagnosis.
What drives the protective effect is not fully understood. Prenatal sex hormones are one candidate. A review of research on prenatal testosterone exposure found associations with both autism development and sex-specific behavior patterns.22PubMed Central. Prenatal Sex Hormone Exposure Is Associated with the Development of Autism Spectrum Disorder And animal research has identified sex-specific effects of elevated maternal testosterone on brain development, including reduced myelination in the brain’s main connective tract specifically in female offspring.23Pediatric Research. Elevated maternal testosterone induces sex-specific neurodevelopmental changes and ASD-related behavioral phenotypes in rat offspring These are early leads, not complete explanations, but they suggest the sex difference in autism is partly biological and not entirely a product of diagnostic blind spots.
Mental Health and Co-occurring Conditions
Autistic girls and women face a particular cluster of co-occurring mental health challenges. A meta-analysis of studies comparing autistic boys and girls found that autistic girls experience significantly more anxiety symptoms, with a gap that widens in older and higher-IQ samples. Trends toward higher depression and overall internalizing symptoms in girls were present but did not consistently reach statistical significance across studies.24PubMed. Sex/Gender Differences in Internalizing Problems of Autistic Children and Young People: A Systematic Review and Meta-Analysis Earlier research found that autistic girls show more internalizing symptoms than autistic boys and more than neurotypical girls during adolescence, with a particular spike in depressive symptoms during early adolescence.25PubMed Central. Autism symptoms and internalizing psychopathology in girls and boys with autism spectrum disorders26PubMed. Sex Differences in Internalizing Problems During Adolescence in Autism Spectrum Disorder
One co-occurring condition that has received increasing attention is eating disorders. In a study of females entering a partial hospitalization program for an eating disorder, 10% already had an autism diagnosis, another 12.5% received a new autism diagnosis during treatment, and clinical suspicion of autism existed for over a quarter of participants total.27PubMed Central. Autism diagnosis in females by eating disorder professionals Research comparing women with anorexia nervosa to autistic women found that their scores on restricted interests and repetitive behavior scales did not differ significantly, even though the autistic group scored higher on other autism measures.28PubMed Central. Autism symptoms in anorexia nervosa: a comparative study with females with autism spectrum disorder The rigid thinking, sensory aversions to food textures, and need for control that characterize some eating disorders can overlap with autistic traits in ways that complicate both diagnosis and treatment. For some women, an eating disorder clinic ends up being the first place their autism is recognized.
Executive Function and Daily Living Skills
There is a counterintuitive finding in the cognitive research: autistic girls may actually score worse than autistic boys on measures of real-world executive function. Parents rate autistic girls as having greater difficulties with executive function overall compared to boys, along with more trouble with daily living skills like managing routines, personal care, and household tasks.29PubMed Central. Sex differences in parent-reported executive functioning and adaptive behavior in children and young adults with autism spectrum disorder More recent work found that autistic girls scored significantly worse than autistic boys on measures of cognitive flexibility, task initiation, emotion regulation, and overall cognitive regulation.30PubMed Central. Sex/gender differences in autistic traits, intelligence and executive functions of school-aged autistic children without intellectual disability
This finding matters practically. If autistic girls struggle more with organizing, shifting between tasks, and regulating emotions in daily life, but are simultaneously masking more effectively in social situations, there is a mismatch between where their support is needed and where their difficulties are visible. A girl who seems socially competent at school may be unable to start homework, manage a morning routine, or cope with transitions at home. The social presentation camouflages the functional struggles.
Safety and Vulnerability
Autistic women and girls face elevated rates of interpersonal violence. A meta-analysis across 24 studies found increased experiences of violence among autistic females compared to autistic males, with a moderate effect size.31Review Journal of Autism and Developmental Disorders. Gender Differences in the Prevalence of Autistic Experiences of Interpersonal Violence: A Mixed Methods Systematic Review and Meta-Analysis A French study focusing on sexual violence found that roughly nine out of ten autistic women in the sample reported having experienced it, with about two-thirds first victimized before age 18 and many experiencing repeated assaults. Being young at the time of first assault strongly predicted revictimization.32PubMed Central. Evidence That Nine Autistic Women Out of Ten Have Been Victims of Sexual Violence
The reasons are likely layered. Difficulties reading social cues and intent, a tendency toward compliance developed through years of masking, social isolation that limits the protective network of friends, and challenges recognizing coercive or manipulative behavior all increase vulnerability. For families and clinicians, this is an area where proactive, explicit education about boundaries and consent is not optional.
The Experience of Late Diagnosis
Because so many autistic women and girls are missed in childhood, a substantial number receive their diagnosis in adolescence or adulthood. The experience is complex. Qualitative research with women diagnosed in middle to late adulthood found that diagnosis facilitated a shift from self-criticism to self-compassion and a greater sense of agency. Participants described a change in identity that enabled greater acceptance and understanding. But adjusting to a reframed life narrative at such a late stage was also painful.33PubMed. ‘I was exhausted trying to figure it out’: The experiences of females receiving an autism diagnosis in middle to late adulthood Research with late-diagnosed women found themes of early marginalization, challenges living outside gendered social norms, the emotional toll of masking, and a significant impact of diagnosis on identity and wellbeing.34Feminism & Psychology. “Fake it ’till you make it”: Authenticity and wellbeing in late diagnosed autistic women
Many women describe decades of collecting other diagnoses first: anxiety, depression, borderline personality disorder, obsessive-compulsive disorder. The autism was the underlying thread, but because it did not look the way clinicians expected, the surface presentations were treated individually while the root went unrecognized. Diagnosis, even late, often reframes those earlier struggles as logical consequences of navigating a neurotypical world without support.
Intersecting Identities and Compounded Disparities
The diagnostic gaps are not evenly distributed. Female and Black populations in the United States are diagnosed later, are more likely to have a co-occurring intellectual disability at diagnosis (suggesting that only the most affected individuals are identified), and are largely excluded from both research and services.35PubMed. Autism presentation in female and Black populations: Examining the roles of identity, theory, and systemic inequalities A Black autistic girl faces the compounded effects of gender bias and racial bias in a system that was built around the profile of white boys. The research on this intersection remains thin, and the gap itself is the finding: these individuals are effectively invisible in the current scientific literature.
Reproductive Health and Sensory Challenges
An area that receives surprisingly little attention is how autism intersects with reproductive health. Autistic people assigned female at birth are more likely to report irregular menstrual cycles, mental health changes related to their menstrual cycle, sensory experiences around menstruation, and poorer reproductive health knowledge and management overall.36PubMed Central. Reproductive health and healthcare experiences in autistic and non-autistic individuals assigned female at birth Sensory sensitivities can make experiences like menstrual cramps, the texture of sanitary products, or the physical environment of gynecological exams significantly more distressing. Hormonal fluctuations may also interact with autistic traits, intensifying sensory sensitivity or emotional dysregulation at certain points in the cycle. This is an area where practical support, from sensory-friendly products to clear, direct health education, can make a meaningful difference but is rarely considered in clinical care.
Gender Identity and Autism
Nonbinary and gender-diverse identities are more common among autistic people than in the general population.37PubMed Central. “I Don’t Understand Their Sense of Belonging”: Exploring How Nonbinary Autistic Adults Experience Gender This makes the phrase “autism in girls” itself an imperfect container for the topic. Some autistic people assigned female at birth do not identify as girls or women, and the social pressures they face around gender conformity may be distinct from those experienced by autistic women who are cisgender. The meta-analysis on interpersonal violence found that autistic gender minorities faced an even higher burden of violence than autistic cisgender women.38Review Journal of Autism and Developmental Disorders. Gender Differences in the Prevalence of Autistic Experiences of Interpersonal Violence: A Mixed Methods Systematic Review and Meta-Analysis For clinicians and families, awareness that gender diversity and autism frequently co-occur matters both for building trust with the individual and for understanding their full risk profile.