My older sister and I are separated by more than a standard deviation IQ-wise, and mine is higher. I believe my sister has at least one learning disability, and I don't have any of which I know. Aside from that, though, we're also very different in terms of intellectual ability levels and intensity. My mother seemed to respond to this by oohing and ahing at even fairly tame accomplishments of my sister's. My sister had an inferiority complex nevertheless. I wouldn't draw any conclusions from my situation, as our family was dysfunctional.
I have just had both my girls re-tested and have exactly 15 points between them, the younger one testing 15 points higher. This morning she asked to be grade skipped to her sisters class (that would be a 4 yr skip :-).
It seems like there might be some unhealthy egotism or competitiveness brewing. In any event I don't see 15 points between siblings as such a vast gulf. Are they very different in terms of other attributes (drive, types of interests, etc.)?
I found these old posts on IQ differences in siblings in general. Maybe something will pique your interest:
http://giftedissues.davidsongifted....114883/Staffing_for_the_Other_Child.htmlhttp://giftedissues.davidsongifted.org/BB/ubbthreads.php/topics/14002/1/Just_curious_siblings.htmlhttp://giftedissues.davidsongifted....2549/Gifted_And_Non_Gifted_Siblings.htmlhttp://giftedissues.davidsongifted.org/BB/ubbthreads.php/topics/36107/Gifted_younger_siblings.htmlhttp://giftedissues.davidsongifted.org/BB/ubbthreads.php/topics/87985/2E_or_ND_ADHD.htmlhttp://giftedissues.davidsongifted.org/BB/ubbthreads.php/topics/80237/Re_Kindergarten_2010_2011.htmlhttp://giftedissues.davidsongifted.org/BB/ubbthreads.php/topics/20569/1http://giftedissues.davidsongifted.org/BB/ubbthreads.php/topics/41858/10.htmlhttp://giftedissues.davidsongifted.org/BB/ubbthreads.php/topics/4534/1.htmlhttp://giftedissues.davidsongifted.org/BB/ubbthreads.php/topics/16739/2.htmlhttp://giftedissues.davidsongifted.org/BB/ubbthreads.php/topics/15252/7.html
