Understanding Autism: Information for Families

Autism is a complex neurodevelopmental condition. While it varies widely in how it affects children, autistic kids often have differences in how they communicate, play and behave. Because most children on the autism spectrum will sit, crawl and walk on time, you may not notice early delays in social and communication skills.

Looking back, many parents can recall differences in ways their child connected with the world as early as their first year. (See What Are the Early Signs of Autism?)

What causes autism?

There is no single, common reason why autistic children have this complex condition. Research so far points to multiple influences, much of it genetic, and also environmental factors.

Scientists continue to learn more about why some children have autism. We currently know that:

• Families do not cause autism. Autistic children are found in families from all backgrounds.
  

• Vaccines do not cause autism. Studies have repeatedly found no credible link between life-saving childhood vaccines and autism. This research, involving many countries and thousands of people, has spanned decades. Unfortunately, there are many untrue claims about children’s health on the internet. These misleading ideas are meant to sound both scary and true so people share them. Usually, they can be traced back to people who will profit from these claims.

• Family medical history and genetics may play a role, and growing evidence supports this link. When a family has one autistic child, the chance that a sibling is on the autism spectrum is 10 to 20 times higher than for the general population. Relatives of children on the autism spectrum are more likely to share some similar social and behavioral traits of those seen among autistic children. However, these characteristics may not stand out enough for a medical diagnosis to be made.

• Most children on the autism spectrum do not have a specific medical or genetic condition that explains their autism. However, autism may occur more often in children with certain medical conditions or genetic differences. These medical conditions can include fragile X syndrome, tuberous sclerosis complex, Down syndrome or other genetic conditions. Infants born preterm are another group that is more likely to be identified as autistic.
  

• Brain differences have been found between some autistic children and non-autistic children.
  

• Environmental factors that may contribute to autism are being studied but are not yet well understood.
  

• Research does not show a causal link between the use of acetaminophen and autism in children, or during pregnancy. Acetaminophen, also called paracetamol and sold under brand names such as Tylenol, is safe for children when taken, or dosed, correctly, under the guidance of their pediatrician. For children older than 6 months, treating fever with medicines like acetaminophen may not be needed unless the child is uncomfortable and having trouble drinking fluids to stay hydrated.
  

How common is autism in children?

About 1 in 31 U.S. children (3.2%) are identified as autistic by the time they are 8 years old, according to a 2025 report from the Autism and Developmental Disabilities Monitoring Network. The report was based on data collected at 16 sites throughout the United States in 2022.

Differences based on gender and other factors

Boys are identified as autistic more than 3 times more often than girls. Overall, the 2025 report showed autism was less commonly identified among non-Hispanic White children than among Asian or Pacific Islander, American Indian or Alaska Native, non-Hispanic Black or African American, Hispanic or Latino and multiracial children. Autism rates ranged widely by location, from 9.7 per 1,000 8-year-old kids in Texas to 53.1 in California. The likely reason is that some populations do not have the same access to screening and evaluations.

Why are more kids being diagnosed with autism?

Overall, the number of children reported to be on the autism spectrum has increased since the early 1990s.

The increase in autism rates could be caused by many factors. For example:

• Families became more aware of autism spectrum disorder.

• Pediatricians began doing more screening for autism, as recommended by the American Academy of Pediatrics. Children are identified earlier, which is a good thing. When more children are screened and diagnosed, more can receive tailored supports they need to thrive.
  

• Schools became more aware of autism, and children began receiving more appropriate individualized education services.

• The autism spectrum has broadened and now includes children with other diagnoses such as intellectual disability, and youth with subtle autistic traits.
  

Changes in how autism is defined & diagnosed

Doctors use a book called the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) to assist in diagnosing autism. In the past, only children with the most obvious or classic signs of autism were diagnosed. But in 2013, the diagnostic criteria for autism changed. This was based on research and clinical experience during the 2 decades since the DSM-IV was published in 1994. Now, children with more subtle traits are being identified as on the autism spectrum.

Several conditions used to be considered autism in the DSM-IV. Those conditions included autistic disorder; pervasive developmental disorder—not otherwise specified (PDD-NOS); Asperger syndrome; childhood disintegrative disorder. With publication of the fifth edition of the DSM, the terms listed above are no longer used; these conditions are now grouped in the broader category of autism spectrum disorder (ASD).

Many people may self-identify as having Asperger syndrome, but professionals no longer use this terminology when making a diagnosis.

The benefits of early identification of autism

Early intervention

Each child on the autism spectrum has different needs. The sooner autism is identified, the sooner families can access early supports and services that are tailored for their child’s needs.

The AAP recommends that all children be screened for autism at their 18- and 24-month well-child checkups. Research shows that starting early intervention can help children and families thrive throughout life.

Co-existing conditions

In addition, children on the autism spectrum may have other medical concerns or needs that require further evaluation and treatment. Commonly co-occurring conditions may include seizures, problems with sleep, gastrointestinal problems (feeding problems, abdominal pain, constipation, diarrhea) and behavioral health issues such as anxiety, ADHD, irritability and aggression.

Remember

Autism can be different for each child. There is no single intervention or treatment that will give every autistic child what they need. Individualized plans, often involving a combination of developmental, behavioral, educational and social-relational strategies, can help in meaningful ways. Autistic children are valued members of our communities and deserve more high-quality research and resources to support their development.

You can reach out to peer support organizations, such as Family to Family Health Information Centers, for local information specific to children with special health care needs and disabilities.

More information

• How Pediatricians Screen for Autism

• What to Do Next When There is a Question of Autism
  

• How is Autism Diagnosed?

• Words of Support for Parents of a Child on the Autism Spectrum