About 1% of the world’s population stutters. That is nearly 3 million American adults.
Onset typically occurs in childhood, between the ages of 2 and 5 years.
Approximately 5% of preschool aged children will stutter. Many of these children will recover, while 20-25% will continue to stutter into adulthood.
Boys are more likely to persist with stuttering than girls, at a ratio of 4:1.