February 4, 2026

expert reaction to study looking at time trends in male to female ratio for autism diagnosis

A study published in The BMJ looks at time trends in a male to female ratio for autism diagnosis.

Dr Monique Botha, Associate Professor in Social and Developmental Psychology, Durham University, said:

“The press release is accurate and the authors acknowledge important limitations including not accounting for commonly co-occurring forms of other neurodivergences. Ultimately, this is a welcome and, frankly, unsurprising finding. The While I don’t fully agree with some of the language used to frame the autism, the analysis itself is robust and closely reflects diagnostic patterns we’ve come to expect over time, particularly the late identification of autistic girls and women and the apparent ‘catch-up’ effect in adulthood. Autism is not a male condition, yet girls struggle to get a diagnosis in a timely or robust manner. Importantly, these diagnostic disparities are not unique to Sweden. We see parallel patterns in the UK and given the UK’s more fragmented diagnostic pathways and constrained infrastructure, there is good reason to think these inequities may be even more pronounced here.” 

Prof Dame Uta Frith, Emeritus Professor of Cognitive Development, University College London (UCL), said:

“The headline ‘Rates of autism in girls and boys may be more equal than previously thought’ is seriously misleading. The excellent study it refers to shows that the sex ratio of 3 boys to 1 girl has stayed remarkably steady over time for children diagnosed below the age of 10. In those diagnosed after the age of 10 the sex ratio declines rapidly, with many more girls than boys being diagnosed. This is true for ages 10 – 15, and even more so after age 15. This is why the study’s model suggests that by age 20 the cumulative male-to-female ratio would reach parity (1:1). The authors rightly ask why it is that females tend to be diagnosed later than males. I wonder whether the late diagnosed females reflect the emergence of a new subgroup of the autism spectrum.” 

Dr Laura Hull, Research Fellow at the University of Bristol Medical School, said:

“This study extends previous research demonstrating relative increases in autism diagnosis amongst females, particularly in adolescents and young adults, and supporting the idea that historically autism has been under-diagnosed in girls and women. The use of population-level healthcare records means that the data are not influenced by self-reporting or recall bias, however there may have been other factors, such as co-occurring mental health conditions, influencing diagnosis timing which were not measured here. Accounting for the whole picture of individuals being assessed is important considering the high rates of conditions such as anxiety, depression, and eating disorders in this group. The authors are not able to explain why the diagnosis ratio is decreasing, as they only had data on when a diagnosis was received, not why it was given. Diagnostic rates are still changing and it remains to be seen whether the male-to-female ratio will continue decreasing, will stabilise, or even will increase again as we continue to ‘catch up’ with diagnosis of girls and women who were missed earlier in life.”

Dr Rachel Moseley, Principal Academic in Psychology, Bournemouth University, said:

“This paper is timely and provides important support for what autism researchers have known for a long-time: that autism is markedly undiagnosed in people assigned female at birth. The study’s longitudinal follow-up of young people is essential, because the signs of autism are often only visible at a slightly later age in girls; this means that studies which only look at toddlers may well miss autistic features which are already present in males but not yet visible in females. Moreover, since the study uses national data, this means that it’s unaffected by biases in who chooses to opt in or opt out to the data.

“Vitally, this study corroborates what studies have already shown us – it’s not the first to show that if you follow children over time so as to account for the later emergence of autistic features in girls, you’ll find that the prevalence of autism is far more equal across male and female children (Burrows et al., 2022) – that study actually found a 1:1 ratio.

“Equally importantly, since we have records of the proportions of autism diagnosed in males and females over the years, these findings – showing us now that autism actually occurs far more evenly across people assigned male and female at birth – support other convincing evidence that very large numbers of autistic women are undiagnosed, especially older undiagnosed women (Stewart and Happe, 2026). And what we know about undiagnosed autistic people is that being undiagnosed is often associated with severe difficulties and even suicidality (Moseley et al., 2025) – so underdiagnosis of autism, like ADHD, should be of serious concern.”

References:

Burrows, C. A., Grzadzinski, R. L., Donovan, K., Stallworthy, I. C., Rutsohn, J., John, T. S., … & IBIS Network. (2022). A data-driven approach in an unbiased sample reveals equivalent sex ratio of autism spectrum disorder–associated impairment in early childhood. Biological psychiatry, 92(8), 654-662.

Stewart, G. R., & Happé, F. (2025). Aging across the autism spectrum. Annual Review of Developmental Psychology, 7.

Moseley, R. L., Marsden, S. J., Allison, C. L., Parsons, T. A., Cassidy, S., Procyshyn, T., … & Baron-Cohen, S. (2025). “A combination of everything”: a mixed-methods approach to the factors which autistic people consider important in suicidality. Autism in Adulthood.

Dr Steven Kapp, Senior Lecturer in Psychology, University of Portsmouth, said:

“This research is consistent with the growing trend for growing diagnosis of autism in women and girls, especially in teens and women. That by young adulthood the diagnosis approaches gender parity in Sweden may reflect their strong national health registries and influence from Gillberg’s ESSENCE concept for broader developmental profiles. Autistic women and girls have often been missed because of subtler behaviours from trends toward more imitation and masking, including more eye contact than male counterparts. Research has revealed that clinical biases contribute to under-recognition of women and girls, which we in the autistic community have long critiqued. 

“Lack of self-understanding may amplify lack of self-acceptance, such as the overrepresentation of autistic females among anorexic people. Greater gender parity in autism diagnosis promotes more safety, wellbeing, and positive relationships for autistic women and girls.”

Reference

Kapp, S.K., Ne’eman, A. (2020). Lobbying Autism’s Diagnostic Revision in the DSM-5. In: Kapp, S. (eds) Autistic Community and the Neurodiversity Movement. Palgrave Macmillan, Singapore. https://doi.org/10.1007/978-981-13-8437-0_13

‘Time trends in the male to female ratio for autism incidence: population based, prospectively collected, birth cohort study’ by Caroline Fyfe et al. was published in The BMJ at 23:30 UK time on Wednesday 4th February. 

DOI: 10.1136/bmj-2025-084164

Declared interests

Dr Monique Botha: “No conflicts of interest which are relevant here.”

Prof Dame Uta Frith: “I can declare no conflict of interest.”

Dr Laura Hull: Laura Hull’s current research is funded by the Prudence Trust, and she has also received funding from the Rosetrees Trust and the Wellcome Trust.

Dr Rachel Moseley: “I have no conflicts of interest”

Dr Steven Kapp: “I have no conflicts to declare.”