For a generation, autism was explained as an exaggeration of the male mind. New population data suggest girls were never rarer, only later to be noticed. The reckoning carries a pointed lesson for India, where diagnosis is already scarce.
Few ideas in psychology have travelled as far, or caused as much argument, as the claim that autism is an extreme version of the male brain. Proposed in its modern form by the Cambridge psychologist Simon Baron-Cohen in 2002, it offered a neat explanation for a striking statistic: roughly four boys were being diagnosed with autism for every girl. Nearly a quarter of a century later the statistic itself is dissolving, and the theory’s author says he regrets the label. New Scientist’s cover feature of 24 October examines what the idea leaves behind.
What the theory claimed
Baron-Cohen’s argument rested on two measurable tendencies. Empathising is the drive to identify what another person is thinking or feeling and respond appropriately. Systemising is the drive to analyse rule-based systems, from train timetables to engines. On questionnaires, women on average score a little higher on the first and men on the second, with wide overlap. Autistic people of either sex, he proposed, sit at the far systemising end, an extreme of the typical male profile. He linked the pattern to testosterone exposure in the womb.
The theory was not without support. A 2018 analysis of more than half a million people confirmed the average sex differences on these questionnaires and found that autistic participants, male and female, scored in the predicted direction. The idea also had an older echo: Hans Asperger remarked in the 1940s that the children he described showed an extreme variant of male intelligence.
Where it frayed
The hormonal mechanism has fared less well. A 2019 experiment involving more than 600 men, far larger than earlier studies, found that giving testosterone had no effect on their ability to read emotions in others. Critics also argued that questionnaires asking people to rate their own interest in machines or feelings partly measure stereotypes, and that describing a mind as male or female confuses small average differences with categories.
The heaviest blow has fallen on the starting premise. In February 2026, The BMJ published a study led by Caroline Fyfe that followed about 2.7 million people born in Sweden between 1985 and 2020, some for as long as 37 years. In total, 78,522 received an autism diagnosis, at an average age of just over 14. Among children under ten, boys outnumbered girls by about three to one. But diagnoses in girls rose steeply through adolescence, peaking at ages 15 to 19 against 10 to 14 for boys, and by about the age of 20 the ratio approached one to one.
A theory that shaped who was seen
If autism is roughly as common in women as in men, then the male excess that the theory set out to explain was at least partly produced by how the condition was recognised. Diagnostic descriptions were built largely on boys. Many girls learn to camouflage, copying social behaviour and suppressing visible differences, at real cost to their mental health. An editorial accompanying the BMJ paper, written by a patient advocate, noted that autistic women are often first diagnosed with mood or personality disorders.
This is the uncomfortable part of the legacy. A theory that told clinicians, teachers and parents that autism is essentially male may have made it harder to see autistic girls. It also fed a popular caricature of autistic people as lacking empathy. Baron-Cohen has addressed both points. In an interview with The Guardian in July 2026, he said he regretted some of the terms he had used because they were easily misunderstood, and called the notion that autistic people lack empathy a myth. He maintains that the underlying findings on empathising and systemising have held up.
Fairness requires two caveats. The Swedish study is observational, comes from one country with an unusually complete health register, and did not account for co-occurring conditions such as ADHD or intellectual disability. Its authors say the sex ratio may be far lower than believed, not that sex differences in autism have been disproved. And biological hypotheses, including the possibility that girls need a higher genetic load before traits become noticeable, remain under investigation.
The view from India
For Indian readers, the debate is not academic. Community studies suggest that roughly one child in a hundred may be on the autism spectrum, which implies well over a million children, yet developmental paediatricians, child psychiatrists and clinical psychologists are few and concentrated in cities. Many children are identified late or not at all.
In that setting, a male template for autism does double damage. Boys are more likely to be brought for assessment in the first place, and a quiet, compliant girl who struggles socially is easily described as shy. Screening checklists validated mainly on boys can miss her. The Swedish data argue for training teachers, anganwadi workers and paediatricians to recognise less obvious presentations, and for following up girls into adolescence, when difficulties often surface.
India has its own assessment instruments and a legal framework that recognises autism as a disability. What is missing is local research on how autism presents in Indian girls and women, and adult diagnostic services of any kind. Both gaps are now easier to justify filling.
What survives
The extreme male brain theory is unlikely to be remembered as simply wrong. It generated testable predictions, drew attention to the strengths in pattern-seeking that many autistic people report, and prompted two decades of data collection. Its failure was one of framing: by attaching a sex to a cognitive style, it turned a hypothesis about minds into an assumption about who could be autistic.
The science has now moved to harder questions: why girls are identified later, how masking affects wellbeing, and what support autistic people themselves say they need. Baron-Cohen’s new Cambridge centre, funded by a 26-million-pound philanthropic gift, says its research will be guided by the priorities of the autistic community. That shift, from explaining autism to listening to autistic people, may prove the more durable legacy.
