When they were 7th graders, since that is when they took the IQ test - WISC-IV for my eldest kid and SB-V for my middle kid - and were officially identified as gifted. My youngest, DD8, has not been tested, though many adults and older kids (friends of my older two) keep telling me she is bright. As I have said on other threads, I declared that the middle one was not college material when she was 4 (she just didn't seem so swift).

However, right after they do something that makes me think they are bright, they will do something that makes me think I have had pets that are brighter than them.