Causes and Factors Associated with Autism
What science currently knows about the origins of autism, based on decades of research.
What science currently knows
Autism does not have one single known cause. Population and genetic studies indicate a major genetic contribution involving many variants and different biological mechanisms. Prenatal and perinatal factors are also investigated, but statistical association should not automatically be interpreted as causation.
Reference: Tick, B. et al. (2016). Heritability of autism spectrum disorders: a meta-analysis of twin studies. Journal of Child Psychology and Psychiatry, 57(5), 585-595.
Genetic Factors
Family, twin and large-cohort studies show a substantial genetic contribution to population variation related to autism. This does not allow individual prediction of whether a child will be autistic or attribution to a single gene.
- Common and rare genetic variants can contribute to autism likelihood.
- For many people, genetic architecture is complex and involves multiple factors.
- Some variants arise de novo, while others are inherited.
- Family history may change probabilities but does not determine an individual diagnosis.
Reference: Grove, J. et al. (2019). Identification of common genetic risk variants for autism spectrum disorder. Nature Genetics, 51(3), 431-444.
Biological Factors
Research also investigates prenatal and perinatal conditions and specific exposures. The strength of evidence and interpretation varies by factor:
- Some medication exposures during pregnancy: certain medications, such as valproate, have known neurodevelopmental risks and require careful medical management.
- Prematurity and perinatal conditions: associated with higher probability of different neurodevelopmental outcomes in population studies.
- Parental age and other characteristics: may show statistical associations but do not individually explain a person’s autism.
Reference: Modabbernia, A., Velthorst, E., & Reichenberg, A. (2017). Environmental risk factors for autism: an evidence-based review. Molecular Autism, 8, 13.
What is still being researched
Science continues to investigate mechanisms and exposures associated with neurodevelopment. For many topics, studies show correlations, inconsistent results or mechanisms that are not yet established:
- Air pollution and other environmental exposures are being studied in observational research.
- The gut microbiome is an active research area, but it does not justify assigning an individual cause for autism.
- Infections, maternal conditions and pregnancy-related factors need to be interpreted according to study type and quality.
- Vitamin D and other biological markers remain under investigation.
- Screen time may relate to development and routines, but observational association does not show that screens cause autism.
Myths and Facts about Autism
Myth: "Vaccines cause autism"
FALSE. Large population studies and reviews find no increased autism risk associated with vaccination, including MMR. The 1998 publication that fueled this myth was later retracted.
Myth: "Autism is caused by the “refrigerator mother”"
FALSE. This outdated and harmful theory blamed mothers. Current science shows that autism has neurobiological and genetic bases and is unrelated to parental affection or care.
Myth: "Every autistic person is a genius in one area"
FALSE. Some autistic people have striking specific abilities, but this is not required for autism. Cognitive profiles, interests and abilities vary widely.
Myth: "Autism has a cure"
FALSE. Autism is a neurodevelopmental condition, not an illness to be “cured.” Support focuses on quality of life, autonomy and appropriate individualized support.
Myth: "Autistic people do not feel affection or empathy"
FALSE. Autistic people feel and connect with others, although they may express affection in different ways. Differences in social communication do not mean absence of feelings.
Myth: "Autism is a linear spectrum from mild to severe"
INACCURATE. Needs, abilities and supports can vary by domain and context. Diagnostic support levels do not summarize the whole person and should not be treated as a fixed scale of value or potential.
Myth: "Autistic children never make eye contact"
INACCURATE. Many may make eye contact, though patterns differ. Some avoid it, others use it atypically. It is not a stand-alone diagnostic criterion.
Myth: "Autism only appears in childhood"
FALSE. Adults may receive a diagnosis later in life. Autism is a neurodevelopmental condition present across the lifespan.
Important notice: This content is exclusively educational and informational. It does not replace assessment, diagnosis or follow-up by qualified health professionals.
Scientific and editorial review: August 18, 2026
O que é autismo?
Uma introdução ao Transtorno do Espectro Autista e às suas diferentes formas de manifestação.
Conteúdo externo selecionado como complemento educativo. As informações e opiniões apresentadas no vídeo são de responsabilidade do canal que o publicou.
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