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Why Autism in Kids? What Really Causes Autism in Children
Kanika Lamba · Founder, Future for Autism · Mother to Mivaan
When a child receives an autism diagnosis, the very first question every parent asks is: Why? What caused this? As an Indian parent, you may be carrying not just worry but also the weight of family opinions, social stigma, and conflicting advice from all sides.
This guide answers the question of why autism occurs in children with the best available science – cutting through myths that cause unnecessary guilt, and helping you understand what we actually know.
1. What Does Cause Mean for Autism?
Autism Spectrum Disorder (ASD) is not caused by a single event or a single gene. It is a neurodevelopmental condition – meaning the brain develops differently from very early on, likely starting in the first or second trimester of pregnancy.
Autism ke Kaaran
Autism arises from a combination of genetic predispositions and early environmental influences that together shape how a child’s brain is wired. Scientists call this a multifactorial cause – many factors, not one.
Think of it like baking – you need a combination of ingredients at the right time. No single ingredient causes the result. Similarly, autism emerges from many interacting biological factors, most of which are present before a child is even born.
Important: In most cases, no single identifiable cause can be found for an individual child. This is normal – it means autism’s biology is genuinely complex.
2. Genetics: The Biggest Factor in Why Autism Occurs in Kids
Across all the research, genetics is the single largest contributor to why a child develops autism. Twin studies have shown that when one identical twin has autism, the other has a 70-90% chance of also being autistic.
Type
What It Means
Example
Inherited variants
Gene changes passed from one or both parents
A parent with mild autistic traits passes relevant genes to child
De novo mutations
New gene changes that arise spontaneously in the child’s cells
A gene mutates for the first time – not inherited from either parent
Copy number variants
Sections of DNA that are duplicated or deleted
Extra or missing copy of chromosome segment 16p11.2
Key Fact: Over 1,000 genes have been associated with autism risk. No single autism gene explains most cases – it is the cumulative effect of many genetic variations working together.
3. Brain Development and How Autism Occurs in a Child
Autism is fundamentally a condition of atypical brain development. Differences in brain structure and connectivity begin forming during the first and second trimesters of pregnancy.
Brain Overgrowth
Many autistic children show unusually rapid brain growth in the first 2 years of life, particularly in the frontal lobes.
Different Connectivity
Connections between brain regions are formed differently – some areas are over-connected, others under-connected.
Mirror Neuron Differences
Differences in mirror neuron function may contribute to social challenges in autism.
Excitatory/Inhibitory Imbalance
The balance between exciting and calming brain signals may be disrupted, contributing to sensory sensitivities and anxiety.
4. Prenatal Factors That May Contribute to Autism in Kids
Factor
What Research Shows
Evidence
Valproate during pregnancy
Strong association with increased autism risk
Strong
Severe maternal infection
Immune activation may affect fetal brain development
Moderate
Folate deficiency
Low folate linked to neural tube issues and autism risk
Moderate
Extreme maternal stress
Associated with modest increase in risk
Limited
Premature birth
Associated with higher autism rates
Moderate
Good News: Folic acid supplementation (400-800 mcg daily) before and during early pregnancy is strongly recommended by AIIMS and WHO.
5. Why Autism Happens More in Boys Than Girls
The Female Protective Effect
Females appear to need a higher genetic load before autism is expressed. This protects many girls from a formal diagnosis even when they carry autism-related genetic variants.
Masking in Girls
Girls are more likely to camouflage their autistic traits, meaning autism is often missed or diagnosed much later – sometimes not until adolescence or adulthood.
Hormonal Differences
Some research points to prenatal testosterone exposure as a potential contributing factor in the higher prevalence among boys.
Diagnostic Bias
Many autism screening tools were developed based on how autism presents in boys – girls’ presentations are often different and may be missed by standard assessments.
6. What Does NOT Cause Autism – Proven Myths
MYTHVaccines cause autism. The 1998 study making this claim was retracted and found fraudulent. Over 30 large studies involving 1.2 million+ children found no link whatsoever.
FACTVaccines are safe and save lives. Autism signs appear at a similar age to vaccinations – a timing coincidence, not causation.
MYTHBad parenting or cold mothering causes autism. The refrigerator mother theory from the 1950s was rejected by science decades ago.
FACTAutism is a neurological difference that develops in the womb. Warm, loving parenting is one of the most important supports for autistic children.
MYTHScreen time or mobile phones cause autism. There is no evidence that screen exposure causes autism.
FACTIf your child shows autism signs, the cause is biological and prenatal – not something they watched on a screen.
MYTHDiet or certain foods cause autism. Food sensitivities in autistic children are a result of autism, not a cause.
7. Sibling Risk: Will My Next Child Also Have Autism?
Recurrence Statistics: If one child has autism: younger sibling risk is 10-20%. If two children have autism: next sibling risk rises to 30-35%. General population risk: approximately 1-2%.
If you are planning another pregnancy, consider speaking with a genetic counsellor at AIIMS Delhi, NIMHANS Bengaluru, or a large tertiary hospital in your city.
8. A Word for Indian Parents: Release the Guilt
Please know this: You did not cause your child’s autism. No one in your family caused it. Autism began in your child’s brain development long before any choice you made – and it is part of who your child is.
What matters now is not the cause – it is the support. Early intervention, a safe and sensory-friendly home, and a parent who understands their child’s needs make a far greater difference to your child’s life than any answer to why.
Apke bachche ko sahi support kaise milegi?
Understanding causes is the first step. The next step is understanding your child’s unique sensory and support profile – so you can help them thrive every day.
Autism happens due to a combination of genetic and early environmental factors that shape how the brain develops before and shortly after birth. No single cause explains all cases – it is a complex mix of hundreds of genes interacting with prenatal and perinatal conditions.
What caused my child’s autism?
In most cases, the exact cause cannot be identified for an individual child. Genetics play the largest role – often involving inherited variants or new de novo mutations. Prenatal factors and advanced parental age may also contribute.
Is autism caused by vaccines?
No. This claim has been completely disproven. Large studies involving millions of children worldwide have confirmed that vaccines do not cause autism. The 1998 study was retracted and found to be fraudulent.
Can bad parenting or screen time cause autism in kids?
No. Parenting style, screen time, diet, or social experiences do not cause autism. Autism begins in early brain development – long before these factors come into play.
Why does autism happen more in boys than girls?
Autism is diagnosed about four times more often in boys than girls, due to the female protective effect, masking in girls, and diagnostic bias in screening tools.
If one child has autism, will the next child also have it?
If one child has autism, the chance of a younger sibling also being autistic is around 10-20%, higher than the general population risk of 1-2%. Genetic counselling can help families understand their specific situation.
Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. If you suspect your child may have autism, please consult a qualified specialist.
Sources: DSM-5, WHO ICD-11, NIMHANS, Action for Autism India, CDC, Nature Genetics, Lancet.
