Autism is usually developed in early brain development in the mother’s womb. But the signs aren’t showed between the ages 2 and 3. “Studies also show that autism is four to five times more common among boys than girls” (Autism Speaks). There is no one cause of autism, just like there isn’t one type of autism. Scientists have found number mutations, and rare gene changes, associated with autism. But the biggest influences of autism are based off of risk genes and environmental factors in early brain development. Some risk factors are parental age at time of conception, maternal illness during pregnancy, and difficulties during birth. An example of difficulties would be where there is periods of oxygen deprivation to the baby’s brain. A mixture
