Risk Factors and Characteristics
1.  Studies have shown that among identical twins, if one child has 
     ASD, then the other will be affected about 36-95% of the time. In 
     non-identical twins, if one child has ASD, then the other is 
     affected about 0-31% of the time. 
2.  Parents who have a child with ASD have a 2%–18% chance of 
      having a second child who is also affected.
3.  ASD tends to occur more often in people who have certain genetic 
      or chromosomal conditions. About 10% of children with autism 
      are also identified as having Down syndrome, fragile X 
      syndrome, tuberous sclerosis, or other genetic and chromosomal 
4.  Almost half (about 44%) of children identified with ASD has average to above average intellectual ability. 
5.  Children born to older parents are at a higher risk for having ASD.
6.  A small percentage of children who are born prematurely or with low birth weight are at greater risk for 
      having ASD. 
7.  ASD commonly co-occurs with other developmental, psychiatric, neurologic, chromosomal, and genetic 
      diagnoses. The co-occurrence of one or more non-ASD developmental diagnoses is 83%. The co-
      occurrence of one or more psychiatric diagnoses is 10%.

1.  Research has shown that a diagnosis of autism at age 2 can be reliable, valid, and stable.
2.  Even though ASD can be diagnosed as early as age 2 years, most children are not diagnosed with ASD until       
     after age 4 years. The median age of first diagnosis by subtype is as follows. 
    - Autistic disorder: 3 years, 10 months
    - Pervasive developmental disorder-not otherwise specified (PDD-NOS): 4 years, 1 month
    - Asperger disorder: 6 years, 2 months
3.  Studies have shown that parents of children with ASD notice a developmental problem before their child's 
      first birthday. 
4.  Concerns about vision and hearing were more often reported in the first year, and differences in social, 
      communication, and fine motor skills were evident from 6 months of age.

Economic Costs
1.  The total costs per year for children with ASD in the United States were estimated to be between $11.5 
      billion - $60.9 billion (2011 US dollars). 
2.  This significant economic burden represents a variety of direct and in-direct costs, from medical care to 
      special education to lost parental productivity.
3.  Children and adolescents with ASD had average medical expenditures that exceeded those without ASD by 
      $4,110–$6,200 per year. 
4.  On average, medical expenditures for children and adolescents with ASD were 4.1–6.2 times greater than 
      for those without ASD. 
5.  Differences in median expenditures ranged from $2,240 to $3,360 per year with median expenditures 8.4–
      9.5 times greater. 
6.  In 2005, the average annual medical costs for Medicaid-enrolled children with ASD were $10,709 per 
      child, which was about six times higher than costs for children without ASD ($1,812). 
7.  In addition to medical costs, intensive behavioral interventions for children with ASD cost $40,000 to 
      $60,000 per child per year.

Many children are living with autism spectrum disorder (ASD), and they need services and support, now and as they grow into adolescence and adulthood. More can be done to ensure that children with ASD are evaluated as soon as possible after developmental concerns are recognized. Read on to learn more about CDC’s new data on ASD.

Findings from CDC's Autism and Developmental Disabilities Monitoring (ADDM) Network help us understand more about the number of children with autism spectrum disorder (ASD), the characteristics of those children, and the age at which these children are first evaluated and diagnosed. These findings are critical for

Promoting early identification of children with ASD;  Planning for services for children and families affected by ASD, and trainings for the professionals who provide those services;  Guiding future ASD research; and
Informing policies that promote improved outcomes in health care and education for individuals with ASD.
The highlights below are pulled from the most recent ADDM Network report, and are based on information collected from the health and special education (if available) records of 8-year-old children who lived in communities in Arizona, Arkansas, Colorado, Georgia, Maryland, Missouri, New Jersey, North Carolina, South Carolina, Utah, and Wisconsin in 2012.

Five Important Facts to Know
1. The estimated percentage of children with ASD remains high. About 1 in 68 or 1.5% of children were 
     identified with ASD based on tracking in 11 communities across the United States in 2012. According to 
     previous reports, the percentage of children identified with ASD increased between 2002 and 2010.  The 
     new report shows no change between 2010 and 2012 in the percentage of children identified with ASD.

2. It is too soon to tell if the percentage of children identified with ASD is still increasing or has 
     stabilized. Here are two reasons why it is too soon to tell: While the average percentage of children 
     identified with ASD in all 11 communities stayed the same, in 2 communities, the percentage of children 
     identified with ASD increased significantly between 2010 and 2012.

     The percentage of children identified with ASD ranged widely by community— in communities where both 
     health and special education records were reviewed, estimates ranged from a low of 1.2% in parts of South 
     Carolina to a high of 2.4% in parts of New Jersey.

     CDC will continue to track ASD over time so as to better understand if the percentage of children identified 
     with ASD is staying the same or continuing to increase.

3. Children identified with ASD are not receiving comprehensive developmental evaluations1 as early as they could be. Most children identified with ASD had concerns about their development noted in their health and/or special education records by age 3 years. Yet, less than half of children with ASD received a comprehensive developmental evaluation by this same age. A lag between first concern and first comprehensive developmental evaluation may affect when children are being diagnosed and connected to the services they need.

4. Black and Hispanic children are less likely to be identified with ASD. Those that are identified with ASD 
     receive comprehensive developmental evaluations later than white children who are identified with 
     ASD. Previous research has not shown that black or Hispanic children have a lower risk than white 
     children to develop ASD. However, since ADDM data showed that black and Hispanic children were less 
     likely to be identified with ASD, it is possible that these children face socioeconomic or other barriers 
     resulting in a lack of or delayed access to evaluation, diagnosis, and services.

5. Schools play a vital role in evaluating and serving children with ASD.  The percentage of children identified 
     with ASD was highest in all communities combined where both health and special education records were 
     reviewed compared to all communities combined where only health records were reviewed.

What Can Concerned Parents Do?
Parents should take two important steps if they suspect their child might have ASD:

1.  Talk to their child's healthcare provider about their concerns.
2.  Call their local early intervention program or school system for a free evaluation of their child.
3.  Parents should remember, it is never too late to get help for their child, and an ASD diagnosis from a doctor 
      is not necessary for a child to begin receiving some types of services. For more tips about what parents and 
      others can do when there is a concern, visit the If You're Concerned website.

A comprehensive, developmental evaluation is a thorough review of how a child plays, learns, communicates, acts, and moves, and whether those characteristics have changed over time. A range of professionals, including teachers, social workers, nurses, psychologists, doctors, and speech-language pathologists, can conduct developmental evaluations. The results of a developmental evaluation are often used by specialists, such as developmental pediatricians, to determine if a child has ASD.