By Toby Rogers at Brownstone dot org.
Good afternoon, Chairman Johnson, Ranking Member Blumenthal, and members of the Permanent Subcommittee:
On July 4, 2015, my then-partner's son was diagnosed as being on the autism spectrum. I was in a Ph.D. program in Political Economy at the University of Sydney where I had access to almost all current scientific and medical journals. I wanted to better understand what was happening, so I went to the CDC's webpage on the causes of autism. As a Ph.D. student I was trained to focus on primary source documents, so I read all of the references in their footnotes.
To my surprise, I quickly discovered that the CDC's narrative did not add up:
Claims that autism is genetic don't make sense because autism prevalence was rising too fast - there's no such thing as a genetic epidemic.
Then the CDC blamed valproic acid, a treatment for epilepsy that is contraindicated in pregnancy, and thalidomide, which was never approved for use in the US - so those factors could only explain a handful of cases stemming from inadvertent use.
Finally, the CDC pointed to advanced parental age; however, the effect sizes were modest and the increase in the proportion of older parents is insufficient to explain the surge in autism prevalence.
Furthermore, the cost of autism was already in the hundreds of billions of dollars a year in the US and yet government was not responding with a sense of urgency.
I changed my doctoral thesis topic to "The Political Economy of Autism" and spent the next four years reading and analyzing nearly everything that has been written on autism prevalence, causation, and cost. In 2019, my thesis passed rigorous external peer review. It's now in the top 10 of the most downloaded doctoral research papers in the history of the University of Sydney.
Since then I've continued my research with Children's Health Defense, as an independent journalist, and as a Fellow at Brownstone Institute.
Here are the facts:
In 1970, the first autism prevalence study in the US found an autism rate of less than 1 in 10,000 children (Treffert, 1970).
According to a study by the EPA, sometime around 1987 the autism rate in the US began to skyrocket (McDonald and Paul, 2010).
The most recent report from the CDC showed that 1 in 31 eight-year-old children in the US in 2022 were on the autism spectrum (Shaw et al., 2025).
That's a 32,158% increase in the last 52 years.
Two massive studies from the best epidemiologists in California show that changes in diagnostic criteria only explain a small fraction of the rise in autism prevalence (Byrd et al., 2002 and Hertz-Picciotto and Delwiche, 2009).
There are 22 studies that claim that vaccines don't cause autism. None of these studies have a completely unvaccinated control group. So unfortunately, if you want to understand what's causing the autism epidemic, these studies are of no use.
Then there are five large genetic research projects - AGRE, SSC, ASC, MSSNG, and SPARK. Together they have produced 501 published papers. The search for "the gene for autism" has consumed over $2.3 billion and researchers have almost nothing to show for it because genes don't suddenly create epidemics - the human genome just doesn't change that fast.
Next there are four large epigenetic research projects (genes and the environment)
CHARGE, MARBLES, SEED, and EARLI. Combined they've produced 437 publications that look at the effects of:
air pollution
pesticides
heavy metals
fluorinated substances
polychlorinated biphenyls
nutritional factors
flame retardants
maternal metabolic conditions (including obesity and diabetes); and
volatile organic compounds.
None of these studies control for vaccines as a possible covariate or confounder, so it's impossible to know the true impact of these variables.
The best available evidence suggests that anything that causes an immune activation event - an infectious disease, an industrial toxicant, or a vaccine - can cause autism. But research from Thomas and...