I have no scientific evidence either way, but I have an understanding of OCD (know someone very well who has OCD on a scale that varies to not much of a problem most of the time, to unable to function). I see OCD sufferers "getting stuck" looking for perfection, and in my speech (my only reference point, I've never met another stutterer) I see myself looking for perfection, perfection in fluency and being "stuck". From that perspective, it feels like there is some sort of connection. I also have OCD tendencies - mainly around checking things, but also having the need to be "level" and have had a stutter all my life. I'm 33 in a couple of months, and have memories of speech difficulties from 30 years ago. Not the best time to write this, it's gone 1am here, but in short I wouldn't be at all surprised to learn of a neurologically proven connection of some sort.