Yes, and your stutter can also disappear simultaneously without therapy. Set myself as the example, when I was 14 y.o my stutter deteriorated as badly as it could and in extremis I could barely talk but after I desensitized myself from stuttering around 15 y.o when I hit my high school my stuttering was nearly gone without therapy and I did not even know what therapy was back then. But it never means you can discredit therapy, at least so far it is the most scientific, experienced, and decent method to reduce your stuttering, although it can also misfire on its clients.