One in 68 children are diagnosed with autism spectrum disorder in the United States. Most of them begin showing the first signs of autism by age 3, but are not getting a diagnosis until they are much older.
Candi Spitz is the mother of 10-year-old twin boys, Brendan and Jaden. She says they were "perfect babies."
The boys passed their developmental milestones as expected.
"The doctors used to remark about how strong they were, how advanced they were," sais Spitz. "They were walking, talking, eating, playing ... everything early."
But that changed when they were 17 months old.
"There were no expressions in their bodies," says their mother. "You would wave their hands, tickle, giggle - anything you could do to get a reaction - and they were blank."
The slowdown in development was first step in diagnosing the boys with autism.
The Centers for Disease Control and Prevention found many children with autism are not being diagnosed as early as they could be.
Even though autism cane be diagnosed as early as age 2, most children are diagnosed at age 4. The lag negatively affects how and when families get the services they need.
"You see the whole gamut. There is not one specific, cookie-cutter diagnosis for autism," says Dr. Norina Ocampo, a South Florida pediatrician who specializes in diagnosing and treating the developmental disorder that makes it difficult for people to socialize and communicate.
"There is no blood test to diagnose autism. It is basically developmental screenings and family histories and observations of the parents," Dr. Ocampo says.
She says doctors continue to rely on a checklist to diagnosis autism - but the questions have changed. The new questions pinpoint behavior in greater detail because every patient falls on a different point of the autism spectrum.
For example, doctors want to know specifically how your child asks you for something.
"Does your child point to ask for things? Does your child point to show you things?" Ocampo says.
Today, twins Brendan and Jaden are primarily non-verbal. They embrace technology to help them communicate.
"He'll take videos of whatever is going on his surroundings and then he will dub his voice on there ... and that's usually how I know if he is sad, happy or whatever it happens to be," says their mother.
Today, she celebrates different types of milestones - looking ahead to a bright future.