Autism Risk Factors for Children

Researchers do not yet know exactly what causes autism, but it is believed to be a combination of genetics and environmental factors. Autism affects children of all races, nationalities, cultures, and economic circumstances. There are, however, a few known factors which correlate with higher rates of autism spectrum disorder (ASD). For example:

• Boys are about four times as likely as girls to develop ASD.
• Families who have one child with autism are more likely to have another. Similarly, families are more likely to have a child with autism if they have relatives with autism.
• Children with certain other medical conditions are more likely to have autism. These conditions include fragile X syndrome (a disorder that causes intellectual problems) and Rett syndrome (a genetic condition occurring almost exclusively in girls, characterized by slowing head growth, intellectual disability, and loss of purposeful hand use). Several other conditions are known to co-occur with autism at high rates.
• Babies born extremely prematurely (before 26 weeks) have an increased risk of ASD.
• Babies born to older parents may be at a higher risk of autism, but more research is needed to establish a clear link.

Vaccines do not cause autism.