This tends to be the first question that most people ask. "What causes autism?" A simple answer to this question is "we don’t know yet". Although current research does not tell us exactly what causes autism, studies do suggest that autism develops from a combination of genetic and environmental influences. Autism is believed to have a genetic basis. For example, statistics show that identical twins have a much higher rate of having autism than fraternal twins. In addition to a genetic basis, research also shows a correlation between autism and neurological differences in the brain.