Let’s start with one unambiguous fact: More children are diagnosed with autism today than in the early 1990s.

According to a sweeping 2000 analysis by the Centers for Disease Control and Prevention, a range of 2–7 per 1,000, or roughly 0.5 percent of US children, were diagnosed with autism in the 1990s. That figure has risen to 1 in 35 kids, or roughly 3 percent.

The apparent rapid increase caught the attention of people like Robert F. Kennedy Jr., who assumed that something had to be changing in the environment to drive it. In 2005, Kennedy, a lawyer and environmental activist at the time, authored an infamous essay in Rolling Stone that primarily placed the blame for the increased prevalence of autism on vaccines. (The article was retracted in 2011 as more studies debunked the vaccine-autism connection.) More recently, he has theorized that a mysterious toxin introduced in the late 1980s must be responsible.

Now, as the nation’s top health official leading the Department of Health and Human Services, Kennedy has declared autism an “epidemic.” And, in April, he launched a massive federal effort to find the culprit for the rise in autism rates, calling for researchers to examine a range of suspects: chemicals, molds, vaccines, and perhaps even ultrasounds given to pregnant mothers.

“Genes don’t cause epidemics. You need an environmental toxin,” Kennedy said in April when announcing his department’s new autism research project. He argued that too much money had been put into genetic research — “a dead end,” in his words — and his project would be a correction to focus on environmental causes. “That’s where we’re going to find an answer.”

But according to many autism scientists I spoke to for this story, Kennedy is looking in exactly the wrong place.

Three takeaways from this story

• Experts say the increase in US autism rates is mostly explained by the expanding definitions of the condition, as well as more awareness and more screening for it.
• Scientists have identified hundreds of genes that are associated with autism, building a convincing case that genetics are the most important driver of autism’s development — not, as Health Secretary Robert F. Kennedy Jr. has argued, a single environmental toxin.
• Researchers fear Kennedy’s fixation on outside toxins could distract from genetic research that has facilitated the development of exciting new therapies that could help those with profound autism.

Autism is a complex disorder with a range of manifestations that has long defied simple explanations, and it’s unlikely that we will ever identify a single “cause” of autism.

But scientists have learned a lot in the past 50 years, including identifying some of the most important risk factors. They are not, as Kennedy suggests, out in our environment. They are written into our genetics. What appeared to be a massive increase in autism was actually a byproduct of better screening and more awareness.

“The way the HHS secretary has been walking about his plans, his goals, he starts out with this basic assumption that nothing worthwhile has been done,” Helen Tager-Flusberg, a psychologist at Boston University who has worked with and studied children with autism for years, said. “Genes play a significant role. We know now that autism runs in families… There is no single underlying factor. Looking for that holy grail is not the best approach.”

Doctors who treat children with autism often talk about how they wish they could provide easy answers to the families. The answers being uncovered through genetics research may not be simple per se, but they are answers supported by science.

Kennedy is muddying the story, pledging to find a silver-bullet answer where likely none exists. It’s a false promise — one that could cause more anxiety and confusion for the very families Kennedy says he wants to help.

Alex Wong/Getty Images

Alex Wong/Getty Images

The autism “epidemic” that wasn’t

Autism was first described in 1911, and for many decades, researchers and clinicians confused the social challenges and language development difficulties common among those with........

© Vox