Oh… and I also found and interesting discussion about it just here:
http://thestutteringbrain.blogspot.ca/2007/04/does-adhd-make-it-harder-to-become-more.html
At the end of the comments, an ADD stutterer wrote some interesting thoughts about it:
“As a genetic stutterer with add i feel ive got something to add here. The medication Dextroamphetamine (dexedrine) worked really well for my add AND stuttering. It allowed me to use my techniques and get those thoughts in before the sounds were being made. Plus, it helped with grades and the ADD. Im still ADD, but ive progressed heavily with my fluency. Im now out of school and a Retail Salesman”
Yay ! 
@kc5jk : otherwise… I’m not particularly clumsy or anything like that… (my drawings and sculpting are not that bad), so I believe it leaves all the coordination problems to my brain and mouth ! 