Autism is something many of us have heard about these days, but very few people feel they fully understand. It can feel mysterious, complex, and sometimes even overwhelming when we ask the simple question: what causes autism?
The honest answer is: there isn’t one single cause. Autism is not like catching a cold where you can point to one virus. Instead, it seems to develop through a mix of biology, environment, and early development. Researchers across the world are still exploring this puzzle, and every year new insights appear. Let’s take a gentle look at some of the main ideas.
Moving Away from Old Myths
Back in the 1940s and 50s, some early researchers believed autism was caused by emotionally cold or distant parenting. The phrase “refrigerator mother” was even used. Understandably, this idea caused deep pain for parents who were unfairly blamed. Thankfully, decades of research have proven this theory wrong. Autism is not caused by lack of love or poor parenting. In fact, many of the strongest advocates for autism awareness have been parents who fought against this harmful belief and many continue to fight for finding the contributory causes.
The Role of Genetics
Research shows that autism often runs in families, meaning genes play a part in how it develops. Twin studies have helped us understand this, showing that identical twins are more likely to both be autistic than non-identical twins.
At the same time, genes aren’t the whole story. Even twins with the same DNA can have different experiences, so environment and development also play a role. Autism is shaped by a mix of factors that make each person wonderfully unique.
Some rare genetic conditions, such as Fragile X or Rett syndrome, can include autistic traits. Identifying these can help families access the right support.
Researchers now believe that many genes work together in different ways, leading to the wide range of strengths and differences seen across the spectrum. Autism can also look different in girls and women, meaning some may be diagnosed later in life. Growing understanding is helping to ensure every autistic person is recognised, valued, and supported.
Environment and Early Development
Genes are only part of the story. Environment also matters. Genes and Environment interaction is described in the scientific world as ‘Epigenetics’. By “environment” scientists don’t just mean pollution or chemicals—they also mean the entire womb environment, pregnancy health, early nutrition, and early life experiences.
For example, research has suggested that very low birth weight, complications during pregnancy, or exposure to certain infections may play a role. None of these automatically cause autism, but they can nudge development in different directions when combined with genetic vulnerability.
Over the years, some environmental theories have caused heated debate, such as the suggestion that vaccines might cause autism. Large studies have since been reported to show there is no convincing evidence of this, and major health bodies continue to reassure parents that vaccines are safe. However, the USA is further exploring the validity and claims made by some of these studies and creating new guidelines for parents to make better informed choices and decisions. Still, the conversation reminds us how important it is to keep exploring science with open eyes, while avoiding blame or fear.
A New Perspective: Primitive Reflexes
One lesser-known but fascinating idea is the role of primitive reflexes. These are automatic movements, some of which are present in the womb and start from the moment of conception. Babies are expected to be born with some already integrated or emerging and are tested for these following birth; such as the moro reflex. They help a baby survive, grow, and begin to interact with the world. Usually, as a child develops, these reflexes become “integrated”—they fade into the background as the brain and nervous system matures or they transition into more mature ‘adult’ reflexes, such as the Moro transitioning into the Adult Startle reflex, and the postural reflexes which develop not only the baby’s posture and physical development but their brain, emotional and learning development.
But sometimes, these reflexes don’t fully emerge, develop and integrate and this can be for many reasons. When that happens, the nervous system may stay in a more “immature” state, making it harder for the child to develop typically, process sensations, regulate emotions, develop smooth movement and coordination.
Here is a list of some of the reflexes and some of the related challenges that may appear when they are not fully integrated to helps us understand how this reflex movement system might be related to many developmental and other diagnosed medical health conditions:
The Fear Paralysis Reflex (FPR):
This is a withdrawal reflex that emerges in the embryonic stage. It is a total body withdrawal away from stimulus that is normal in the womb. The foetus reacts to stimulus by withdrawing inward and freezing. As tactile awareness develops, withdrawal upon contact gradually lessens. It is thought that this reflex is the first step in learning to cope with stress.
Ideally, the FPR merges into the Moro reflex and becomes inactive before birth. If the FPR is not fully integrated at birth, it may contribute to life-long challenges related to fear. People with the FPR active may often feel very anxious and tend to veer towards a negative mindset, which can prevent them from easily moving forward and to living a meaningful, interactive life.
An active FPR often goes hand-in-hand with an un-integrated Moro reflex. Possible effects of the FPR being unintegrated include:
- Shallow, difficult breathing
- Underlying anxiety or negativity
- Insecure, low self-esteem
- Depression/isolation/withdrawal
- Constant feelings of overwhelm
- Extreme shyness, fear in groups
- Excessive fear of embarrassment
- Fear of separation from a loved one, clinging
- Sleep & eating disorders
- Feeling stuck
- Elective mutism
- Withdrawal from touch
- Extreme fear of failure, perfectionism
- Phobias
- Aggressive or controlling behaviour, craves attention
- Low tolerance to stress
The Moro Reflex: (also called the infant startle reflex):
It is an automatic response to sudden change in sensory stimuli and/or a sudden change of any kind such as bright light, a change in body position, temperature, loud noise, intense touch, etc.
Effects of this reflex being retained include:
- Easily triggered, reacts in anger or emotional outburst
- Poor balance and coordination
- Poor stamina
- Poor digestion, tendency towards hypoglycaemia
- Weak immune system, asthma, allergies and infections
- Hypersensitivity to light, movement, sound, touch & smell
- Vision/reading/writing difficulties
- Difficulty adapting to change
- Cycles of hyperactivity and extreme fatigue
- A retained fear paralysis reflex might make a child extra anxious or withdrawn.
- A retained tonic labyrinthine reflex could affect balance and posture.
Tonic Labyrinthine Reflex (TLR):
This reflex provides the baby with a means of learning about gravity and mastering neck and head control outside the womb. It is important for giving the baby the opportunity to practice balance, increase muscle tone, and develop the proprioceptive and balance senses. The TLR interacts with other reflexes to help the infant start developing coordination, posture and correct head alignment.
It is vital for the TLR to do its job because correct alignment of the head with the rest of the body is necessary for balance, eye tracking, auditory processing, muscle tone and organised movements – all of which are essential for the development of our ability to focus and pay attention.
Possible effects of an active TLR include:
- Balance and coordination difficulties
- Hunched posture
- Easily fatigued
- Poor muscle tone
- Difficulty judging distance, depth, space and speed
- Visual, speech, auditory difficulties
- Stiff jerky movement
- Toe walking
- Difficulty walking up and down stairs
Asymmetric Tonic Reflex (ATNR):
This is important for developing homo-lateral (one-sided) movements. When the infant turns his head to one side, the arm and leg of that side automatically extend. In the womb, the ATNR provides the necessary stimulation for developing muscle tone and the vestibular system. It assists with the birth process, providing one of the means for the baby to “corkscrew” down the birth canal. The ATNR also provides the ability to learn hand – eye coordination. By six months of age, this reflex should evolve into more complex movement patterns.
If the ATNR remains active it plays a significant contribution to academic problems at school and may be possible reasons for:
- Dyslexia
- Reading, listening, hand writing and spelling difficulties
- Difficulty with maths
- Confused handedness
Symmetric Tonic Reflex (STNR):
This reflex is not a primitive reflex. It is a ‘transitional’ one. It’s an important developmental stage that transitions the baby from lying on the floor up to being able to crawl. At this stage in development, movement of the head is automatically linked to movement of the arms and legs. If the STNR remains active, it is another main cause of inability to function in school. This is because up and down head movements remain linked to arm and leg movements, making school work effortful and difficult.
The effects of an active STNR may present as:
- Poor, hunched posture
- Headaches from muscle tension in the neck
- Difficulty writing and reading
- Difficulty sitting still
- “W” sitting
- Difficulty copying from blackboard
- Ape-like walking
- Vision disorders
- Find it difficult to stay on task
Spinal Galant reflex:
The Spinal Galant & Spinal Pereze Reflexes work in conjunction with the ATNR to help the baby’s journey down the birth canal. It is also thought to help babies balance and coordinate the body for belly crawling and creeping. It is thought to be connected to bladder function because a high percentage of children who are bedwetting past the age of five have an active Spinal Galant reflex. Possible long term effects of these refelexes being active/retained/unintegrated are:
- Bedwetting
- Poor endurance
- Attention difficulties
- Hip rotation to one side/scoliosis
- Poor concentration
- Poor coordination
- Poor posture
- Poor short-term memory
- Fidgeting/hyperactivity
Other reflexes that Rhythmic Movement & Neurodevelopmental Consultants may assess and work with are the following foot, hand and oral reflexes – the Babinski, Plantar, Palmar, Hands Pulling, Grasp, Amphibian, Rooting, Suck and Babkin reflexes and their role in learning and development especially for speech, coordination, writing and language development
Some possible long term effects of an unintegrated/retained/active foot, hand and oral reflexes are:
- Speech delay or difficulties
- Swallowing problems
- Poor social behaviour
- Dribbling and drooling
- Poor manual dexterity
- Poor pencil grip
- Handwriting difficulties
- Loose, easily sprained ankles
- Toe walking
- Flatfooted or walking on sides of feet/hip rotation
- Difficulty expressing written ideas
When certain reflexes don’t fully develop or “integrate” in early childhood, it can affect brain and nervous system development. This may help explain some of the challenges and behaviours seen in children and adults with conditions like autism, ADHD, dyslexia, dyspraxia, and others. Even after these reflexes have naturally developed, they can sometimes become active again following a traumatic event or ongoing stress, which may contribute to conditions such as PTSD.
As mentioned above, the good news is, that by using the rhythmic movements, there is research emerging showing that these reflexes can be integrated long after their typical developmental time and at any age.
The Gut and Brain connection to Autism:
Leaky Gut:
Some children experience what’s known as “leaky gut,” where the lining of the gut becomes damaged and allows tiny food particles and proteins to pass into the bloodstream instead of being properly digested or removed. Research suggests this can contribute to inflammation and certain changes in behaviour.
Because of this, some parents choose to try diets that remove certain proteins—such as gluten (found in wheat) and casein (found in dairy)—and notice improvements over time. Others focus on healing the gut by reducing additives and preservatives, or by supporting their child’s nutrition with supplements.
It’s always best to make these changes with the help of a qualified Nutritional Therapist, who can check for any deficiencies and create a safe, balanced plan.
Changing a child’s diet can be challenging, especially when they have sensory sensitivities or prefer routine foods. But with patience, gentle encouragement, and very small steps, many families find it’s possible—and see positive changes along the way.
Vitamins and Minerals: Supporting Your Child’s Health
Families that explore nutritional support to help their child’s brain, gut, and overall health have used vitamins B6 and B12, along with magnesium, DMG (Dimethylglycine), Folinic Acid that all play important roles in the body, including supporting brain function, nervous system health, digestion, detoxification and important cellular processes.
- Vitamin B6 supports healthy nerves and brain function, helps make red blood cells, and plays a role in mood and immunity. When levels are low, some children may have more trouble with sleep, irritability, or focus.
- Vitamin B12 is important for brain health and the body’s natural chemical balance. Some people don’t absorb enough B12 from food, so extra support can sometimes help.
- Magnesium plays a part in hundreds of body processes, including muscle and nerve function, bone strength, and energy. It’s found in foods like leafy greens, grains, and nuts.
- DMG (Dimethylglycine) helps the body with a process called methylation, which supports things like antioxidants, hormones, and brain chemicals. Some parents and researchers have noticed changes in speech and communication when using DMG supplements.
- Folinic acid (Leucovorin) is a special, ready-to-use form of vitamin B9 (folate). It’s often used when the body can’t easily process regular folic acid. Folinic acid helps with DNA and red blood cell production, supports growth during pregnancy, treats certain types of anaemia, and can also reduce side effects of medicines such as methotrexate.
- 5-MTHF is another active form of folate that the body can use straight away. Folinic acid turns into 5-MTHF in one extra step, but both can be helpful—especially for people with an MTHFR gene variation that makes it harder to process regular folic acid.
Together, these vitamins and minerals help the body work well at a deep, cellular level — supporting natural detoxification, brain function, and healthy development. While supplements can be helpful for some children, they’re just one piece of a bigger picture. Working with a team of trusted professionals helps ensure any plan is safe, tailored to your child’s needs, and gives them the best opportunity to thrive.
The Immune System and the Gut
Another important reason to think about diet and gut health is that around 70–80% of the immune system lives in the gut. The gut lining is full of helpful immune cells that work together with trillions of good bacteria and other microbes to keep the body healthy and protected.
If the gut lining becomes damaged (often called “leaky gut”), it can make the immune system weaker and more sensitive, leaving a child or adult more likely to pick up infections or react to things in their environment.
A baby’s gut health starts developing during birth, as they pass through the birth canal and come into contact with their mother’s natural bacteria. This first exposure helps the baby’s immune system begin to develop. After birth, breastfeeding and the baby’s surroundings continue to shape and strengthen their gut microbiome — the community of helpful bacteria that supports overall health.
What about Vaccinations?
The MMR Debate
There are different viewpoints about the MMR vaccine and autism. Most of the research that says there is no link between the two comes from large population studies, which look back at children’s health records — these are called epidemiological studies.
These studies are different from biological studies, like the one originally carried out by Andrew Wakefield, which involved direct medical testing on the children taking part. Most of the evidence used to show that the MMR vaccine is safe is based on these large-scale record-based studies, rather than on biological investigations.
For further informed decision making, here is a section (Section 112) of the 2001 Medical Research Council’s (MRC) ‘Review of Autism Research: Epidemiology and causes:’
‘112. The aforementioned reviews were unanimous in their conclusions that a causal link between the MMR vaccine and “autistic colitis” and ASDs was not proven and that current epidemiological evidence did not support this proposed link. The Institute of Medicine report noted that “this conclusion does not exclude the possibility that MMR vaccine could contribute to ASD in a small number of children, because the epidemiological evidence lacks the precision to assess rare occurrences of a response to MMR vaccine leading to ASD”4. We recognise that, as with most epidemiological studies of causation, this remains a theoretical possibility. More extensive research would be necessary to provide evidence for the biological plausibility of a suggested causal link between viral infections and ASDs (as this is currently not robust), as it would be for other proposed causal factors.’
In section 113. of this same report, it states,
‘…it is important to recognise that epidemiological studies cannot prove that vaccines are safe but can only exclude specific adverse effects with a certain degree of confidence…’
This can be easily found on line here…
Andrew Wakefield’s original study has been followed up in later research. For example, Singh and colleagues replicated similar work in 2002 and 2009. In their 2002 study, they looked at 125 children with autism and found unusual MMR-related antibodies in 60% of them, while none were found in a control group of 92 non-autistic children. Most of these children also had antibodies that could affect the brain, suggesting a possible link between MMR and immune activity in the nervous system. The 2009 study confirmed these findings.
It’s important to remember that only more biological studies — studies that directly test and measure children — can help prove or disprove any link. Research gains credibility when findings are replicated in similar studies. Arguing over reports in the media doesn’t help parents, who need clear, evidence-based information to make decisions for their children.
In his book, Callous Disregard, Wakefield himself has admitted that he was “naive” in how he collected blood samples from children, which is seen as the ethical issue that discredited him professionally. Importantly, Wakefield and his colleagues never claimed that the MMR vaccine causes autism. Their conclusion was careful: they observed a possible gut condition in children and suggested that further research is needed to explore whether it could be related to neurodevelopment and vaccines.
The exact quote from the research paper states,
”We have identified a chronic enter colitis in children that may be related to neuropsychiatric dysfunction. In most cases, onset of symptoms was after measles, mumps, and rubella immunisation. Further investigations are needed to examine this syndrome and its possible relation to this vaccine.’
New Revelations
In 2025, U.S. President Donald Trump asked Health Secretary Robert F. Kennedy Jr. to look into the rising rates of childhood illnesses, including autism.
This investigation has brought attention to previously hidden research and raised questions about the practices of some health and scientific organisations. It has also led to reviews of vaccine schedules and further investigations into the companies involved and revealed research relating to the health and neurodevelopment of vaccinated and non-vaccinated children.
This has helped spark a movement for parents to have more information and make informed choices about vaccines, in the USA where in some states, vaccination was mandatory to attend school.
We have yet to see how this new insight of information will affect the UK and the rest of the world.
In Summary
So, what causes autism? The best answer right now is: a mix of factors.
- Genetics may provide a predisposition but are notfound the be the one cause.
- Environmental influences (before, during and after birth) may shape how that predisposition shows up;
- Gut integrity and the microbiome affects brain and immune system development;
- Primitive reflexes and early development could set the stage for how a child’s nervous system grows and responds to the world.
No single cause explains autism in every person. In fact, it may be better to stop searching for the cause and instead think of autism as many different pathways leading to a similar set of traits and behaviours, many of which are found in other diagnoses.
It is very important to remember that autism is diagnosed on observed and reported behaviours to a clinician who makes the decision on whether these meet the diagnostic criteria of the time. Diagnostic criteria has varied over the years and this is believed by some to be the reason for the increase in the increase in autism spectrum disorders/conditions.
Why This Matters
Understanding the causes of autism isn’t about blaming or finding fault. It’s about building compassion and creating better support. When we see autism as the result of complex biological and developmental processes, we can move away from harmful myths and towards practical ways of helping a person with the challenges they feel are affecting their daily living and capabilities and support them in developing the skills and life they aspire to achieve and fulfil their dreams and full potential.
For example, if primitive reflexes play a role, then simple daily movements might give a child more comfort and further support their development, learning and confidence. If genetics set the stage, then family awareness can help spot traits earlier, provide some understanding and may facilitate assessments, support, interventions and therapies sooner. If environment adds its influence, then supporting and educating parents in the possible environmental influences that may contribute to developing autism can help them make informed decisions and this can make a positive empowering difference to them and better outcomes for the whole family.
A Note on Identity
It’s also important to recognise that many autistic people don’t see their autism as something to be “fixed.” For them, autism is a part of their identity—a different way of thinking, sensing, and being in the world. Exploring causes should never be about labelling someone as “broken.” Instead, it should be about creating environments where all autistic people can thrive, while respecting the diversity of all human minds.
The more we learn and share, the better we can support autistic people to create the life they want and reach their full potential—and perhaps even fulfil dreams that would not exist without their unique way of being in the world.