Are genetics or environmental factors the primary cause of autism?

Dr. Emma Allen-Vercoe

Department of Molecular & Cellular Biology, University of Guelph, Guelph, Canada.

Prof. Jeremy Nicholson

Chair In Biological Chemistry, Head of Department, Department of Surgery and Cancer, Imperial College, London UK

Dr. Stephen Scherer

Director of The Centre for Applied Genomics, and Senior Scientist, The Hospital for Sick Children, Toronto, Canada

Dr. Derrick MacFabe

Director and Principal Investigator of the Kilee-Patchell-Evans Autism Research Group, University of Western Ontario, London, Canada.

Join the discussion : What is the primary cause of autism: genetics or environment?

38 thoughts on “Are genetics or environmental factors the primary cause of autism?

  1. Aspergers is not Autism per say and is a more of a Genetic problem. I have 3 of 6 with Autism not Aspergers. 2 of the 3 will have a Normal out come due to our intervention. I think what you are trying to say is yours does not fit this type of Autism and you are right there is a genetic component that is different from our children. Reflux not sure what you mean about this one as most get reflux due to virus like ulcers.

    • i believe its a combo of both gen/enviro. what my question is “has anyone focused on if this combo trigger is still affecting our children on the spectrum now that they are exposed to it outside of the womb?? and why hasn”t this video been given airplay or for that matter the government addressing this issue globally there hasn’t been enough airplay addressing autism i am the parent of a beautiful girl that sees the world differently

  2. I forgot to mention within 1 week of starting the diet my son smiled at me and called me MOM. Oh man, I promised my self i would not cry while writing this….. shoot, oh well. We went from that at 2.5 years of age to normal level at 6 …. YOU CAN TOO.

  3. Thank you for your effort in the fight. I have long suspected the allergic link or so I thought. I did the no gluten diet for 2 of my 3 autistic kids. I have an almost normal out come now. What we see when Dominik gets foods that are high carb or gluten he acts out, gets a head ache, goes to sleep and wake to vomit. When he was little it was just sleep. I am sad to say the oldest child the mom will not let me try the diet, so we do not know if it could help her. She craves carbs and is aloud to have them. I have work really hard with the other 2 and it is finally an answer for us at least. It would make sense why what we did worked .
    Athan my 9 year old was 4 weeks when he was first given an antibiotic and 10 weeks for the first shot…. He cried for 2 days, then we lost him… NO cooing, no eye contact, just screaming…. Evan to my breast milk. I have to go to a soy protein removed no milk formula, then slowly we got him back then we had to do NO gluten/ or wheat so he would not scream. He does not have silac. He is normal today and very bright. Makes me very sad that all I had was Jenny and her story and video for help. The doctors just were no help I was on my own. I do not go to doctors for anything now we find a holistic way to fix things and eat more base product real fruit NO juice, eggs, not over processed stuff.

  4. You are absolutely correct, and that is why I posted my earlier article (which is starting to move rather rapidly through the community). Please, if you have not read it completely, here is a copy of the link:

    It may seem “too technical” if you are not used to certain areas of human medicine, but as a good reader I know that you will simply skip over those places and continue. Upon completion, you will understand a good bit more about developmental disorders than most of your therapists and clinicians … and you can then continue making excellent decisions.

    Congratulations and keep it up!

    J. Patrick Maone

  5. I also have a spectrum child. Last year i put both my children on a diet of no processed food – Got rid of bread preservative and all the other bad stuff. The change in my children was not mind blowing but it was definatly an incremental improvement. Professionals have told me diet has no effect !!!!! I challenge this to the enth degree. If we could improve the diets of our children, avoid all the toxins in our environment our children would have an even chance of enjoying life to a greater degree. Please open your minds.

  6. Your documentary just screened over here in Australia and I was really grateful to finally see more attention given to the diet and gut/brain connection and Autism. I definitely agree with what was stated in this documentary and am excited to see the potential for great things to come from it especially for Autistic children, but I also believe that vaccines have a role to play in this as well.

    The immigrant families that were shown, did they and/or their children receive vaccines before entering the country. Most of the children were having ear infections before they received antibiotics, could the vaccines be the laying the foundation by affecting the immune systems of genetically susceptible children and making them more prone to infections before the antibiotics came and destroyed so many beneficial bacteria, and the harmful bacteria was then able to cause the damage that it did?

    Within my own 8 children, 6 were vaccinated and 2 were not, amongst the 6, 3 have Autism, 1 has ADHD (and possible Aspergers), 1 has a severe language disorder and 1 has food allergies and mood swings they also have/had Gastrointestinal disorders, Urinary tract infections, ear infections, Asthma, Eczema, Psoriasis, food allergies and chemical sensitivities etc while my two youngest unvaccinated children have none of their siblings disorders. I admit that my two youngest have never had antibiotics but they have also had no need, no serious illnesses and they are the picture of health. They were also raised on the same diet as their siblings so the change in diet is not a factor.

    I am grateful again for bringing some well needed attention to this issue, but I hope that this does not stop the research that also needs to be done about the vaccine issue, as there is a lot of new information and studies pointing at problems and risks with vaccination. You are so right when you say we all need to get together and solve this, the sooner we share information and listen to others presenting their views with respect, the sooner real progress will be made to help not only our children with Autism but all children.


    • Hi I totally agree , I have two autistic children , both onsets happened after the shots. Here’s an extra thought ; were you yourself imunised , & if so wouldnt your own imunity have been passed on to your children, mabee its a compound effect, why wernt we affected by our shots

      • Hi Bruce, I was vaccinated but this was back in the early 1970’s so I hardly got the amount that our poor children do now, funny thing though, is I still got Measles even though I was vaccinated for it, but I definitely got Mumps and Chicken Pox naturally, so my children would have received some of my natural immunity to it, fortunately.

        I would think that my mother would have had a much better range of gut bacteria than myself, and I think we are in most cases getting a much more dysfunctional gut being passed on down the line as well as a much more toxic lifestyle, food, dependance of prescription and OTC drugs, environment in general being inherited as well as an ever increasing amounts of vaccines. It would be nice if someone could do some study in to all of these factors, there is so much we do not know and our children are suffering because of it.

        • Immunity doesn’t get passed on like that sorry, and my whole family has always been vaccinated and raised on a wholesome diet. 6 kids, homemade bread and veges from the garden. One has aspergers, a different brother has reflux, the child who was on antibiotics lots was my sister- no autism there. Small studies are not efficient in proving anything, the margin of error is too big, they only lead to larger studies where actual conclusions can be made. If you want your child to have RHD or perhaps lifelong health affects from measles AS WELL as autism, don’t judge health professionals for not encouraging you.

  7. There is more up to date work on autism.
    As an inflammatory disease with defective immunity, assisting the immune system as well as a modified diet is required.
    Hence the use of GcMAF assists 80% of autistic children.
    This also assists CFS and other inflammatory diseases.
    CFSDiscovery (
    Maybe the ABC could follow this up.
    Maybe the ABC could check the MacKeon Report to the government.
    Dr Ivan Hooper

  8. Always had a feeling autism and the gut maybe related since my little boy experienced anti biotics for ear infections followed by-gut problems . Now need help for him as autistic almost a six year old .I did a detox ( 7 day fast supervised type supported by vitamins colemas etc) which interestingly ended with strong emphasis on taking flora capsules to replenishing “good bacteria” that was lost during fast. I felt “brand new ” at then end however i am reluctant to try on someone so young as it seems bit extreme ? but want to try something along same principles…..

    • Tony, look into GAPS diet devised by Dr Natasha Campbell McBride as stated in post here by J Berg. This diet repairs the gut and in some kids works miracles. It works on the principle of only eating foods the gut can easily digest, monosaccarides and specific carbohydrates, thus assisting repair. There are GAPS practitioners in Australia.


  9. I work with many families with young adults on the spectrum in post school education. My question for you is that I am seeing a significant amount of parents that have different forms of cancer. Is there a link between the parents immune system and the child with AS? Is it the stress of raising not one but often 2 or more children on the spectrum? This health issues puts financial and emotional strains on the family and often the young adult is also carer for their parent. Is there any research into this that you could recommend to me ?
    Yes, I see many families where the one or both parents are on the spectrum – so I do believe there is a genetic link. Do you define environmental to include foods? yes, I believe there is a gut issue but am not a scientist.

  10. Just pointing out the connection to the MS story on Catalyst (23rd August) where there is again a possible link with bacteria. What over diseases may be linked – epilepsy?

    • The research on the role of gut bacteria in disease is just starting to open up. I can’t speak to the link with epilepsy, but some of Dr. MacFabe’s research does address the prevalence of epilepsy in children with ASD’s and why and how the two might be connected.

  11. A documentary on autism (and those trying to treat it) and not one mention of GAPS or the doctor in the UK successfully treating autism through diet? Seriously? Will there be a sequel featuring (or at least including) Dr. Natasha Campbell-McBride, the author of The Gut and Psychology Syndrome? Her research and successful work is making the North American researchers in the documentary look like they are far behind. Don’t these people talk to each other? Surely a documentary on the subject would have turned up her name or at least the diet she developed (GAPS diet). Or, if nothing else, the basis of the GAPS diet: the Specific Carbohydrate Diet developed in the 1950s by Dr. Haas and developed further by Dr. Elaine Gottschall. The SCD has been proving that a gut with an overabundance of “bad” bacteria causes all sorts of health problems (GI diseases as well as auto-immune, neurological, circulatory, etc. diseases).

    Please, please, please do a follow up documentary or something to include the SCD and GAPS. So many people can be helped. I know it saved my life when no doctors could.

    • I have just watched this programme on Four Corners in Australia. Whilst an hour’s programme may not be able to give all angles, the fact that diet and gut issues are being aired is a major breakthrough in Australia. What we need here is for someone to take the facts and run with it here – my son is under one specialists, with a lot of expensive supplements and special diet – so far, little change, but we are persevering.

      • Keep persevering Diane. Once you find the right diet and right supplements the results can be wonderful. After 2 years of diet modification, tests, trials and tears I have seen my son improve significantly. Read as much as you can. Investigate the MINDD foundation for resources. Search out Biomedical support groups. They are all here in Australia. It is worth while and there are many people like myself seeing recovery.


  12. Over the years I have had many injuries and have been on numerous medications. I remembered an older man when I was a young man tell me that I should take something he called .. honey gaul…. a mixture of a tablespoon of Honey and a tablespoon of pure Apple Cider Vinegar…. mixed with water to taste…. one hour before breakfast and dinner. I thought it a joke… but when I tried it after taking all of these meds… I tossed those medical supports away and have not been on them since…. that was in 1997 … my health and blood pressure and pains almost disappeared…
    My point is that in support of the gut bacteria… this is a natural method of supporting the digestive system… try it and see what happens…. it just might amaze you ….

    • I have read about taking apple cider vingar, and the reason it works is because it gives the gut the acid it needs to break down food properly and then the body can assimilate the nutrients. A lot of people have unhelathy gut flora due to diet and envrionmental toxins, this combined with low stomach acid can prevetn the body receiving nutrietns. I am not an expert, but serioulsy keen on researching about health. If you look for elaine hollinhsworths’s books, she deatials the main helath problems which lead to others, from her extensive research about her own health issues. she also uses trusted Dr.s research about health. Very trustworthy information to look at.

  13. Having watched the TV program, “The Nature of Things”, on December 7, 2011 on CBC Television, I became interested in the plight of autistic children and their parents. My primary concern is the use of antibiotics for young children, since the beneficial bacteria in the gut is destroyed. This is of no minor concern, since the mass of bacteria in the stool of a healthy person can be about 30%, most of it being beneficial. Beneficial bacteria in the gut aid in digestion and counteract the harmful forms of bacteria, such as clostridium bacteria which is responsible for many other infections and diseases.

    From the TV program, it was suggested that toxic substances, produced in the gut through improper digestion, could have been absorbed by the blood stream and been deposited in the brain where it affected the neurotransmitter cells.
    The brains of young children can also be affected by mercury, lead, and excess copper.

    The quickest way to restore the digestive balance of the gut is through probiotics. Other helpful nutitional supplements can be found in the book “Prescription for Nutritional Healing” by Phyllis A. Balch.

  14. I object to the way the question is posed: ““ARE GENETICS OR ENVIRONMENTAL FACTORS THE PRIMARY CAUSE OF AUTISM?”
    In this, as in other matters, we need to get away from either/or thinking.
    It would be and/and. Environmental factors affect people with a certain genetic predisposition more. We all know that for instance allergies ‘run in families’. If a member of a family prone to allergies has a runny nose and itchy eyes when a certain pollen blows, do we blame heredity or environment?

  15. Bravo to all who were involved in this show and thank you for bringing attention to the autism disorder and highlighting some intriguing avenues of research.
    Please forward to Ellen Bolte my congratulations and support for her hope, persistence, and brave efforts in searching for answers regarding her son’s condition.

  16. Hi there,

    Have you investigated Lyme as one of the potential bacteria causing Autism? ( Lyme can cause massive GI problems, and if a child is born with lyme, then that may cause Autism, (pregnant mother with unknown Lyme infection). Lyme bacteria is metal sensitive, (lead/mercury,) it explains why some children regress after receiving vaccines and some don’t. It also keeps the immune system from properly balancing levels of yeast. Lyme can also cause add/adhd, bipolar disorder and much, much more. ::

  17. I am new to this disease and having just been advised that two of my grandchildren, out of the 5 children in the household, have been determined to be autistic… I need information…and true information on how to be of assitance. It is a terrible thing to see the future of our country … approximately 10% … diagnosed with this disability. I have been in contact with our Government officials who say … we are working hard to … ! I can fill in the blanks… as are the parents and the other children who are to young to understand… they just see two of their siblings getting special attention…and it is causing unwarrented stress within the family. I am not amused ..Thanks… JHG

    • You are absolutely correct, and that is why I posted my earlier article (which is starting to move rather rapidly through the community). Please, if you have not read it completely, here is a copy of the link:

      It may seem “too technical” if you are not used to certain areas of human medicine, but as a good reader I know that you will simply skip over those places and continue. Upon completion, you will understand a good bit more about developmental disorders than most of your therapists and clinicians … and you can then continue making excellent decisions.

      Congratulations and keep it up!

      J. Patrick Maone

Leave a Reply