05/03/2009 05:12 am ET Updated May 25, 2011

WORLD AUTISM AWARENESS DAY: Awareness Is Great, But Cure Alludes

t's a devastating diagnosis for any parent to hear. And more parents than ever are learning that their child has autism: it now afflicts about 1 in 150 children, according to the Centers for Disease Control. It's four times more prevalent in boys than in girls.

As World Autism Awareness Day - designated by the United Nations as April 2 - winds down, the spotlight is on why the disorder is on the increase, why the causes still elude researchers, and why early diagnosis is so important.

"We know autism is on the rise and we know there is a genetic predisposition," says Dr. Cathy Pratt, board chairperson for the Autism Society of America ( "The controversy is over what is the trigger that actually causes it to occur. A lot of research is on what triggers it. I think that we will find that there are multiple causes. It's not like a broken arm."