Something to keep in mind in all of this:studies have shown that parents are actually very good at identifying gifted children - often actually underestimating their children's abilities. (I don't have to do the how yes, it depends, blah blah thing here do I?) I can't find the references right now (if I find it I'll post it), but it's worth keeping in mind when you doubt 'other people's children'.
See, and I take those studies to indicate that parents who judge their children to be gifted
and are willing to put their money where their mouths are and have the kids IQ tested, are pretty good at identifying gifted kids. Those who go around stating that the kids are gifted but don't seek testing to support it -- it's anyone's guess as to how accurately they id their kids' abilities.
eta: I certainly won't argue with the quote from the link that states that teachers aren't particularly adept at iding gifted kids in their classrooms, though.
