Skip to main content
Click to toggle navigation menu.

Autism, The Facts

Autism spectrum disorder (ASD) is a developmental disability that is caused by differences in how the brain functions.  People with ASD may communicate, interact, behave and learn in different ways. Signs of ASD begin during early childhood and usually last throughout a person’s life.


  • About 1 in 36 children has been identified with ASD.
  • ASD is about 4 times more common among boys than among girls.
  • ASD is reported to occur in all racial, ethnic, and socioeconomic groups.

Risk Factors and Characteristics

  • 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.
  • Parents who have a child with ASD have a 2%–18% chance of having a second child who is also affected.
  • Children born to older parents are at a higher risk for having ASD.


  • Research has shown that a diagnosis of autism at age 2 can be reliable, valid, and stable.
  • Even though ASD can be diagnosed as early as age 2 years, most children are not diagnosed with ASD until after age 4 years.
  • Studies have shown that parents of children with ASD notice a developmental problem before their child’s first birthday. 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.

Source: Center for Disease Control’s Autism and Developmental Disabilities Monitoring (ADDM) Network.

Autism 101 Webinar

For additional information, join the FREE Autism 101 webinar, by Dr. Marlene Sotelo, BCBA-D, MT-BC, Executive Director, Els for Autism Foundation®.

Developmental Milestones

The signs of autism often exist before a child’s 2nd birthday.  Below are some early social communication milestones that are important to look for as your toddler grows.

Source: Marcus Autism Center, NIH Autism Center of Excellence

Social & Language Milestones at age 9 months

Social Milestone:

  • Smiles and laughs while looking at you

Language Milestone:

  • Vocalizes often with babbles
  • Reaches for things he/she wants
Social & Language Milestones at age 12 months

Social Milestone:

  • Responds by looking when name is called
  • Enjoys playing social games such as peek-a-boo

Language Milestones:

  • Uses gestures such as giving, showing and pointing
  • Uses consonant sounds and a few simple words (examples: “mama”, “baba” for bottle)


Social & Language Milestones at age 18 months

Social Milestone:

  • Plays pretend with dolls or stuffed animals
  • Imitates words you say and actions in play

Language Milestones:

  • Uses at least 10 words
  • Says many different consonant sounds
  • Identifies familiar people and body parts
Social & Language Milestones at age 24 months

Social Milestone:

  • Shows interest in playing with other children
  • Puts many actions together during play (examples: stirring, pouring juice, feeding a doll)

Language Milestones:

  • Uses at least 50 words
  • Makes simple sentences such as “Mommy go outside” ,”What’s that?”
  • Identifies objects when named
Social & Language Milestones at age 36 months

Social Milestone:

  • Enjoys imaginative play with others
  • Takes turns in conversation

Language Milestones:

  • Responds to questions
  • Uses longer sentences
  • Follows two-to three-step instructions
  • Uses speech that is understood most of the time