Experts disagree on the prevalence of Asperger's syndrome, and estimates range from 1 in 250 to 1 in 5,000 children, explains the U.S. National Library of Medicine. Males are at least three times more likely than females to be affected.
Asperger's became more loosely defined over a period of 20 years, beginning in the 1990s, according to Psychology Today. This has led to concerns that the disorder is over-diagnosed and the prevalence is lower than current estimates.
Asperger's syndrome is an autism spectrum disorder, according to U.S. National Library of Medicine. Symptoms include impaired social skills and communication skills. Individuals with Asperger's syndrome generally have average or above average intelligence and are high functioning on the autism spectrum.