I assume my dad is GT...he graduated from the Naval Academy in engineering and he is one of the smartest people I know.
I have two brother's that tested gifted (one of them I saw his results by accident and he is PG) and he was one of those kids that just knew stuff without being taught and could sleep through class and get 100s on everything.
My dh's sister's son tested gifted and I would assume he is PG just from knowing him. He skipped a grade and could have skipped another (he earned several credits for 9th grade in middle school and only needed to take one online summer school class to skip to 10th grade) but he has a brother in 10th grade and his mom doesn't want them both going to college the same year.
One of my sons has Asperger's and tests gifted (right at the cut off). I often wonder if that is accurate because they didn't use a WISC but used the RIAS and I wonder if his anxiety/Asperger's suppressed the score a bit but it could be right on.
My younger son tested PG on the K-ABC-II and then just under PG on the WISC when I private tested (why our school system doesn't give a WISC I'll never know). I KNEW he was a smart cookie. I didn't know he was that out there. It was kind of a shocker.
As for myself, I had one older brother and one younger brother who were REALLY out there. I always, always felt less than gifted (and was never tested). Chances are I am not PG but I assume I am at least gifted.