“What causes autism?” is a question surrounded by more misinformation than almost any other in health. Here’s what the evidence actually says — and, just as importantly, what it clearly rules out.
Autism is largely genetic
Autism is one of the most heritable of all developmental conditions. It runs strongly in families and involves the combined effect of many genes influencing early brain development. This is why autism is described as neurodevelopmental — it reflects how the brain is wired from very early on, not something that happens later or is caused by upbringing.
There isn’t a single “autism gene.” Rather, many genetic variations each contribute a small amount, in different combinations for different people — part of why autism looks so varied.
Other contributing factors
Alongside genetics, some factors during pregnancy and birth are associated with a modestly higher likelihood of autism — such as parental age and certain prenatal factors. These influence probability; they don’t “cause” autism on their own, and they’re not anyone’s fault.
The vaccine myth — clearly disproven
Let’s be unambiguous: vaccines do not cause autism. This myth originated from a single 1998 study that was found to be fraudulent, was retracted, and led to the author losing his medical licence. Since then, very large, high-quality studies involving millions of children have found no link whatsoever between vaccines and autism. The science here is settled.
The myth persists partly because autism is often identified around the same age routine vaccinations are given — a coincidence of timing, not cause.
What doesn’t cause autism
Autism is not caused by parenting, screen time, diet or “refrigerator mothers” (a long-discredited idea). Autistic children are born autistic.
Understanding, not blame
Autism is a natural variation in human neurology, not a disease to be blamed on anyone. If you’re seeking clarity for yourself or a family member, a thorough autism assessment is the right step. Read autism in adults or book an appointment.
This article is general information, not medical advice.