My daughter was tested at the school she previously attended, but just tested as a high achiever, which is what I expected. I've never taken her for outside testing because she gets along with other kids her age and seems to respond appropriately to things. She is very highly motivated to learn and catches onto things very quickly.
I originally sought help for my son because I suspected he was on the spectrum. He was having random horrible tantrums and would scream if another kid even looked at him. He also wanted only me all the time. He wouldn't even look at his father or grandparents. And he has always spoken very well, but there was a point where he only spoke a made-up language for about 3 months straight. I knew he was very intelligent and probably quite gifted, but I didn't realize just how gifted he is.
I read about the whole indigo children thing and it seems fairly accurate for him. My son seems to be able to do things and just knows things and I have no clue how or where he learned them. He also seems to not be motivated at all to prove his intelligence, for the most part. He had me convinced for about a year that he was color blind until he slipped one day and told me the right color when I asked him. He really tries to manipulate me and everyone around him.
