Researchers have ditched the autism-vaccine theory. Here’s what they think actually causes it.

There’s a gaping hole between science’s understanding of autism and the public’s.

Of all the issues doctors have explored in children’s health, none has been more exhaustively researched than the question of whether vaccines are linked to autism. After hundreds and hundreds of studies in thousands of children, “We can say with almost as much certainty than anybody could ever say that vaccines don’t cause autism,” Mayo Clinic autism researcher Dr. Sunil Mehta told me.

And yet the fear that they do remains stubbornly persistent, as a current measles outbreak in Minnesota shows. The virus is spreading among unvaccinated children — in this case, Somali-Americans in Minneapolis, after anti-vaccine advocates targeted their parents with a misinformation campaign.

Now 51 people, most of them children, are very, very ill.
Today, about one in 68 US children has autism — a rate that’s remained unchanged since at least since 1990, though there’s been a steady increase in awareness and diagnosis. And it’s the parents of some of these children who are among the most vocal proponents of the vaccine-autism link — in Minnesota and elsewhere. Many are frustrated, confused, and desperate for an explanation for why and how their children got the disorder.

It doesn’t help that doctors have long struggled to explain what exactly causes autism if vaccines don’t — many medical theories have been debunked and then replaced by new ones.
The medical community is getting closer and closer to finally zeroing in on the cause.

I recently talked to half a dozen researchers on the cutting edge of this work to find out what they see as the latest and best evidence for what might trigger autism. They were excited about their new understandings of the genetic basis for autism — what they view as the most promising area of research on the disorder right now.

They also talked about recent advances in grasping how particular genetic mutations change the biology of the brain in ways that cause autism symptoms.

More blurry is their research on the non-genetic (or environmental) contributors to autism, like pollution or medications. Here’s a quick rundown of what we know about what causes of autism — from most well-established to least well-established.