Many scientists have believed that genetics accounted for 90 percent of a child's risk for autism. A new study, however, suggests that environmental factors could play a much larger role.
The research looked at nearly 200 pairs of twins, and found, to the researchers’ surprise, that a greater number of fraternal twins shared autism than identical twins. Fraternal twins share only half their genes with each other.
According to NPR:
"Scientists have long suspected that there's been an environmental contribution to autism ... and previous studies have shown that it may occur in the early stages of pregnancy."
For a truly eye-opening look at the causes of autism, watch this interview with Dr. Natasha Campbell-McBride -- a physician who cured her own son of the disorder.