That is certainly a valid concern and you're right; you don't want to use it as an excuse. I talked about it by discussing how it was hard to deal with growing up but that as I got older, I pursued opportunities in spite of my stutter. Instead of making it sound like a crutch and something that held me back, I talked about how it challenged me to do things I didn't always feel comfortable with and how it ultimately helped me become a more confident, well-rounded individual. Basically, I framed what is generally perceived as a weakness as a strength.