Can a person with a stutter be cured?

I had never met anybody with a stutter until recently and I got to thinking, can it be cured? I know there are several things that can cause a stutter, both physical and psychological. So if the problem is psychological, is there a better chance of getting cured? By the way, the guy that I met who has a stutter sings beautifully which is very interesting I think. Anyhow, any thoughts?