I get this question almost more than any other. Or, I'm also asked "are you Irish," and usually by people who are obviously trying to do one of two things:
  1. Place my kilt-wearing into a portion of their brain that has been, through previous experience with kilts and such, conditioned for their understanding of my wearing it.
  2. Show off that they know that kilts are Scottish (or show off that they "know" kilts are Irish - quotes are intentional).
I can usually pick out which they are by the look on their faces - if they look quizzical, it's #1. If they look smug, it's #2.

My answer to the asker is generally "yes, but I'd wear it even if I wasn't because it's so darned comfortable." If I get the "Irish" comment, I look at them strangely while I say "Well, kilts aren't Irish. I just wear this because I like it."

Perhaps it's a bit immature, but I really get a private kick out of deflating the egos of people who are smug about having bad information. For more on this, please see my sig. ;)