Today is World Autism Awareness Day, a day to bring attention to a disease that is affecting an increasing number of children and families each year. A new report from the Centers for Disease Control and Prevention (CDC) finds that autism diagnoses are up sharply since figures were last released in 2009 — but frighteningly, no one knows why.

The CDC report released last week found a 78 percent increase of cases of autism from 2002 to 2008. The incidence of autism is now 1 in 88 children across the board and 1 in 54 boys in the U.S. The latest data come from medical and school records collected from more than 300,000 8-year-olds in 14 states across the country in 2008.

One theory on the jump in cases is the increase in awareness — thanks to events like today's World Autism Awareness Day — that has led to increased identification and diagnosis of autism in younger children and minority children who weren't being diagnosed before. This may be responsible for some additional cases, but health experts warn that this is not responsible for the entire trend.

Another theory for the increase in autism cases could be due to changes over time such as a greater incidence of older fathers contributing sperm with small genetic abnormalities to their offspring. Again, this may represent a small increase, but is not be responsible for the huge increase noted in the CDC report.

Still, the numbers are perplexing, particularly to those who track them.

"People want answers to what's causing autism and to why we're seeing such an increase in identified cases," said Thomas Frieden, director of the CDC, in an interview with the Wall Street Journal. "So do we."

Hopefully, researchers will figure out what is causing this increase before the proposed changes to the definition of autism go into effect at the end of the year, further blurring the lines between actual incidences of autism and diagnoses of kids who fit a specific definition.

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