In terms of symptoms and general properties, there are many similarities between stuttering and tourette syndrome. Here's a summary: 1.) People who stutter and people with tourette syndome both have excessively high concentrations of dopamine in an area of the basal ganglia, the striatum, compared to non-psychotic fluent people. 2.) Both follow a waxing and waning pattern, meaning during some months the symptoms are less severe and other months they're worse. 3.) Both overly affect males. I've seen male:female ratios between 4:1 all the way to 7:1, which I suspect comes from sampling different age groups. I suspect that because stuttering female children are much more likely to spontaneously recover from stuttering compared to stuttering male children. 4.) Both are made temporarily worse by anxiety, but are not directly caused by anxiety. 5.) Both involve genetic factors that are hereditary (they can be passed on to offspring). 6.) Both begin in childhood.