How common is autism?
Autism can be diagnosed in children, sometimes as early as 18 months old, as well as in adolescents and adults. Many different environmental, biologic and genetic factors may make an autism diagnosis more likely. Risk factors may include one’s genes,
advanced parent age and a family history of having autism, state the Centers for Disease Control and Prevention (CDC).
Autism is not caused by poor parenting or vaccinations. It occurs in all racial, ethnic and socioeconomic groups. According to the CDC, about 1 in 44 children in the United States is diagnosed with ASD.
What goes into an autism diagnosis?
Doctors use behavioral and developmental tests to make an autism diagnosis, because medical tests, such as blood tests, cannot diagnose the disorders. Currently, an autism diagnosis includes a developmental screening by a physician that checks if children
are learning basic skills for their age, or if there are delays. Development screening is recommended at regular well-child doctor visits.
Because several factors can influence the development of autism, a separate comprehensive evaluation is also used to diagnose ASD. This evaluation may include looking at the child’s behavior and development, interviewing the parents, genetic testing,
hearing and vision screening and neurological and other medical testing.
Characteristics of autism may be observed during early childhood, but autism tends to go undiagnosed until much later in life, according to the World Health Organization (WHO).
What are the signs of autism?
Here are six signs to look for in early childhood:

At 6 months
Few or no big smiles and limited eye contact.

At 9 months
Little or no back-and-forth sharing of sounds, smiles or facial expression.

At 12 months
Little or no response to name, no back-and-forth gestures like reaching or waving.

At 16 months
Little or no words.

At 24 months
Very few or no meaningful two-word phrases.

At any age
Avoids eye contact, delayed language development, prefers to be alone.