I'd say it's only an issue if you have really severe stutter and can't keep conversation with other people. In most cases, it's not stutter per se that's the problem, but the effect it has on you (less sociable, no self esteem etc) and that can be worked on. By having a mild stutter, I'd say that you shouldn't have too much problems. There will be people who will reject you because of your speech impediment but everyone has something that others may find a deal breaker. So no, I wouldn't consider myself undateable and I wouldn't consider my stutter a disability. It's a struggle but it's far lesser struggle than having an autism or Aspergers. I consider it a quirk and it doesn't bother me too much nowadays.