WASHINGTON (AP) -- Research is under way to determine why minority children are more likely to receive diagnoses for autism later than white children.

And there is new work to increase awareness of the warning signs so more parents know they can get help even for a toddler.

Experts have some clues. Preliminary research at Baltimore's Kennedy Krieger Institute suggests the delays are due in part to cultural differences in viewing developmental milestones.

Researcher Rebecca Landa says how doctors interact with parents could also result in delayed diagnoses.

The American Academy of Pediatrics says it's possible to detect autism as early as 14 months of age. There are no cures, but therapies are believed to be more effective when started earlier. Yet on average, U.S. children aren't diagnosed until they're about 4 1/2 years old.

The preliminary research, based on a small study, is in the Journal of Autism and Developmental Disorders.