What causes autism?
- Dr Harry Woodward
- Dec 15, 2025
- 3 min read
AI generated image
(And why the answer is both reassuring and surprisingly fascinating)
If you’ve ever found yourself at 2 a.m. Googling “What causes autism?” while also trying to remember where you left your cup of tea (spoiler: it’s in the microwave), you’re not alone. This is one of the most common questions parents ask in clinic — and a completely understandable one.
Let’s walk through what we know, what we don’t know, and what actually matters for your child’s wellbeing.
So… what does cause autism?
Here’s the simple version:
Autism is caused by differences in brain development — mostly influenced by genetics — and definitely not caused by anything parents did or didn’t do.
Current research shows that autism arises from a combination of:
Genetic factors (lots of small variations, rarely one single gene)
Prenatal factors (how the brain develops during pregnancy)
Very early brain development differences
Crucially, autism is not an illness, and it’s not something your child “caught.” It’s a neurodevelopmental difference — a different way the brain processes information, communicates, and experiences the world.
For further reading, the NHS has a clear overview of autism causes here: Autism - NHS Overview
Genetics: The biggest piece of the puzzle
If you imagine a recipe, genetics provide most of the ingredients.
Research suggests that autism tends to run in families, and scientists estimate that genetics account for a large proportion of the likelihood of being autistic.
But before you start wondering whether Uncle Bob’s love of spreadsheets played a role:
No single “autism gene” exists. Instead, there are hundreds of genetic variations that may subtly influence how the brain develops.
A helpful summary of the science can be found on the CDC website: Autism - facts
Environment: The supporting ingredients (not the cause)
When we say “environment,” we’re not talking about screen time, parenting styles, food colouring, air pollution, or the number of wooden toys in your house.
We’re talking about biological factors during pregnancy that influence early brain development — things like:
Differences in how the brain grows in utero
Prematurity
Certain pregnancy-related complications
Even here, these factors don’t cause autism on their own. Instead, they may gently nudge the developing brain along a particular pathway if the genetic recipe is already in place.
A balanced explanation is available in this NICE guideline overview: NICE guidelines (Autism)
What doesn’t cause autism (despite what the internet may claim)
Let’s bust a few myths quickly and kindly:
Parenting style? Nope.
Vaccines? Absolutely not (this has been conclusively disproven by mountains of evidence).
Too much screen time? No.
Too little screen time? Also no.
Your child’s preference for organising dinosaur figurines by colour? Definitely not.
Parents do not cause autism. Full stop.
If you need permission to exhale now, please do.
For reassurance, here’s a reliable NHS myth-busting page: Autism myths
The most important takeaway
Understanding the exact cause of autism isn’t nearly as helpful as understanding how your autistic child experiences the world.
Autism isn’t something to blame, fix, or cure — it’s a neurotype, with its own strengths, challenges, and beautifully unique qualities. What matters most now is:
noticing what helps your child feel safe,
supporting their communication style,
celebrating their interests,
and building an environment where they can thrive.
And if you’re parenting an autistic child?
You’re already doing one of the most powerful things: seeking to understand.
At NeuroDiverseKids.co.uk, our clinicians are here to help you make sense of assessments, behaviour, sensory needs, school challenges — and all the questions that pop up along the way. You don’t need to figure this out alone.
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