In The Politics of Autism, I discuss various ideas about what causes the condition. Contrary to the lies of Trump and RFK Jr., vaccines do not cause autism.
So what does?
More than two dozen studies have looked at the MMR vaccine and autism and not found a link. These include a massive 2019 study in the Annals of Internal Medicine, which looked at more than 600,000 children in Denmark. These studies have been done in different styles and different countries. All have reached the same conclusion.
Rather than vaccines, scientists say genetics plays the dominant role—both inherited traits and spontaneous mutations in early conception.
In other words, ASD is largely out of our control. More often than not, people with heritable genetic traits for autism don’t even know it....
Genetic and environmental factors together most likely result in an increased risk of someone developing autism, says Heather Volk, a professor at Johns Hopkins University Bloomberg School of Public Health. She and other researchers have studied air-pollution exposure during pregnancy and found an association with autism.
Part of the frustration with autism risk is there isn’t much we can do to control it. Staying healthy during pregnancy, however, can help minimize risk.
Janine LaSalle, a professor of microbiology and immunity at University of California, Davis, says there is evidence suggesting that maternal health risks—such as obesity, weight gained during pregnancy and gestational diabetes—can increase the risk of having a child with autism.
Another protective action pregnant moms can consider is taking a prenatal vitamin with folic acid and iron supplementation. This is especially important in the first month of pregnancy and so should be started when a woman is trying to conceive, says LaSalle.
“If there was a single smoking gun it would have been found by now,” says LaSalle. “It really is the complexity of the formation of the human brain, and there’s just so many things that can influence it.”
