The GDA in Denver has done some studies on this; but it is all very limited.
Now, it is important to understand that all of this will give, at most, are statistics. My favorite example for this is that "men are in average higher than women" is a true statement inferred from statistics. I am taller than many men, and that doesn't contradict the statement, nor it disproves it. In the end, you can't predict anything for one particular individual.
Yes! Thank you for stating this so clearly! <applause>
The little bit of study that has been done suggests that MOST (not all!) siblings are within 10 IQ points of one another. That is in no way a guarantee that all are. For that reason, this is inaccurate:
So we have all heard that siblings are within 5-10 points of each other and children are 10 points or so from parents
In fact, the only thing that we know for sure is that NOT all siblings are within 10 points of one another because not all who were studied were. One exception disproves the rule.
The meager evidence does seem to support the "Test one, test 'em all" approach though, since there is a good possibility of GTness across families.
I haven't read anything that I can recall about parents IQs and their kids. Certainly nothing as throughly cited as the "10 point siblings" study.
