Five to fifteen percent of the population is suffering from a form of Dyslexia. The learning disability can be compensated with proper therapy, training & equipment. The gender balance for dyslexia seems to be pretty even between males and females.
Dyslexia main manifestation is difficulty developing basic reading skills in elementary school children due to the ability to associate visual symbols with verbal sounds. While motivational factors must be determined in reviewing poor performance, dyslexia is considered an inborn trait and rarely arises from environmental factors after the brain has matured beyond infancy.
Other believe while it may be inborn, it can also be the lack of phonic training when learning to read, and the preponderance of the whole language system
Studies have shown whole performing reading tasks, those with Dyslexia show reduced activity in the left parietal cortex.