Story highlights The new number is a 30% increase from two years ago

Autism remains more common in boys than in girls

The report doesn't say why the incidence of autism is rising

One in 68 U.S. children has an autism spectrum disorder (ASD), a 30% increase from 1 in 88 two years ago, according to a new report released Thursday by the Centers for Disease Control and Prevention.

This newest estimate is based on the CDC's evaluation of health and educational records of all 8-year-old children in 11 states: Alabama, Wisconsin, Colorado, Missouri, Georgia, Arkansas, Arizona, Maryland, North Carolina, Utah and New Jersey.

The incidence of autism ranged from a low of 1 in 175 children in Alabama to a high of 1 in 45 in New Jersey, according to the CDC.

Children with autism continue to be overwhelmingly male. According to the new report, the CDC estimates 1 in 42 boys has autism, 4.5 times as many as girls (1 in 189).

"We look at all of the characteristics of autism," says Coleen Boyle, the director of the CDC's National Center on Birth Defects and Developmental Disabilities.

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"So we look at the age in which they're identified. We look at their earliest diagnosis. We look at co-occuring conditions that these children might have, other developmental disabilities, whether or not they have intellectual disability, so essentially their IQ."

The largest increase was seen in children who have average or above-average intellectual ability, according to the CDC. The study found nearly half of children with an autism spectrum disorder have average or above-average intellectual ability -- an IQ above 85 -- compared with one-third of children a decade ago.

The report is not designed to say why more children are being diagnosed with autism, Boyle says. But she believes increased awareness in identifying and diagnosing children contributes to the higher numbers.

More than 5,300 children are represented in the data contained in the new report, she says.

"We comb through records. We accumulate all that information and then each one of those records is reviewed by a specialist to make sure that that child meets our autism case definition," says Boyle. The definition of autism is unchanged from the 2012 report.

One thing that hasn't changed over the years is that children are still being diagnosed late. According to the report, the average age of diagnosis is still over age 4, even though autism can be diagnosed by age 2.

The earlier a child is diagnosed with autism, the better their chances of overcoming the difficulties that come with the disorder.

"It's not a cure, but it changes the trajectory," says Dr. Gary Goldstein, president and CEO of the Kennedy Krieger Institute and professor of neurology at Johns Hopkins University.

"We need to continue our efforts to educate the health care community and general public to recognize the developmental problems associated with ASD and other developmental disorders at earliest age possible, so that intervention can be initiated, bad habits can be avoided and families will know what's wrong with their child," says Dr. Max Wiznitzer, a pediatric neurologist at Rainbow Babies and Children's Hospital in Cleveland who diagnoses and treats children with autism.

This new report is based on 2010 data, when the children were 8 years old (born in 2002).

Since 2000, the CDC has based its autism estimates on surveillance reports from its Autism and Developmental Disabilities Monitoring Network.

Every two years, researchers count how many 8-year-olds have autism in about a dozen communities across the nation. (The number of sites had ranged from six to 14 over the years, depending on the available funding in a given year.)

In 2000 and 2002, the autism estimate was about 1 in 150 children. Two years later 1 in 125 8-year-olds was believed to have autism. In 2006, the number grew to 1 in 110, and then the number went up to 1 in 88 based on 2008 data

Boyle acknowledges these statistics are not necessarily representative of the entire United States because the information is drawn from 11 states, not a national cross-section.

But she adds that the 11 areas represent 9% of all 8-year old children in the United States in 2010, which Boyle says gives the CDC a "good picture of what's going on in those communities with regards to autism."

However, experts such as Wiznitzer and Goldstein are concerned that the new CDC report is not describing the same autism that was present and diagnosed 20 years ago, when the numbers first shot up.

"Twenty years ago we thought of autism with intellectual disability. We never looked at children who had normal intelligence" -- doctors never considered that high-functioning children had autism too, says Goldstein.

Wiznitzer believes written reports can't definitively determine whether a child has autism. You need to see the child to complete a diagnosis, which the CDC experts did not have the opportunity to do.

"This report tells us that there's a significant number of children in the states where they were assessed that have social differences and a pattern of behaviors that can be represented by ASD, but may also be due to other conditions that superficially can have similar features, such as social anxiety, ADHD with social immaturity and intelligence problems," he says.

And while the CDC reports it is still seeing a higher prevalence of autism in white children relative to African-American and Hispanic children, "there's a greater percentage of people of color and in females being diagnosed now," says Scott Badesch, president and CEO of the Autism Society of America . "We're also seeing a great increase of diagnosis above the age of 8 in girls."

The new statistics raise significant concerns about access to care, because autism is a lifelong disorder and the need for services only begins at diagnosis, says Robert Ring, chief science officer for the advocacy group Autism Speaks.

"Behind these numbers are real people," he says. "Every one of these numbers is a family that's coming to terms with the implications of the diagnosis for the lifespan of their loved one."

"We need a plan to respond to these numbers, a national strategy for autism, and leadership has to come from Washington," because every congressional district is affected, says Ring.

There are still disparities in awareness and access to care among minorities and poorer families, which can have a direct impact on a child's outcome, he says.

In the end, it's not so much about the final number. As Goldstein puts it, 1 in 68 or 1 in 70 doesn't really matter. What matters, he says, is that we now know this is not a rare disorder, and it's important that each individual gets the help they need to have the best quality of life.

All agree that a comprehensive national strategy that includes the research community, policy makers, educators and caregivers is necessary to find solutions for people who live with autism.

One of the biggest problems, in Goldstein's eyes: "We don't have enough trained professionals to do this." He adds, "it's hard to get paid to do this."

In many cases, insurance does not pay, even in states that have passed laws requiring health insurance to cover autism, he says.

When poorer parents are told their child has autism, Badesch says, they realize that to get services, they must get on a waiting list or get Medicaid. In many states, he says, Medicaid doesn't cover autism therapy for young children during the most critical developmental period, which is essential to a better outcome.

Autism is definitely a "have and have-not" disorder, he says, and the new numbers show even more people will need services that are lacking.