Gifted Issues Discussion homepage Forums Parenting and Advocacy Are siblings usually gifted also?

Hi there! I was curious to know if people who have one gifted child have others as well. My DS7 is PG and we also have a DS who just turned 3. He seems very smart but in a much different way than his older brother. DS7 is a perfectionist and a talker and it is easy to see his giftedness. DS3 is very laid back, silly and really can't be bothered with most things. I think that their different outward personalities make them seem more different than they actually are. So, anyway, just curious if siblings are usually gifted as well... I want to be prepared;-) I've also read that siblings are usually within 10 IQ points of eachother - is that anyone's personal experience?

Thanks so much for any comments!!!

I've read the same - that siblings are typically within 10 or so points of each other.

Honestly, I don't think that's the case with my two... my son is at least highly gifted (hard to say with his 2e-ness) and picks things up the very first time he learns about them... while my daughter... she's a good student, meets the school's goals, but doesn't really seem to go much beyond that, and often has a difficult time learning new things. I'd say she's maybe mildly gifted.

I believe that the place I've heard that 10 point rule come from is the Gifted Development Center. I've never seen any actual studies done to support this. The GDC, I believe, came up with that based on what they see with kids whose parents bring them in for testing. I'd have to expect that there is some bias there, though, in that they are quite expensive and something like 84% of the kids they assess wind up with at least mildly gifted IQ scores. Thus, I'd suspect that parents who are willing and able to spend $1-2K on testing for multiple kids are pretty darn sure before putting out the money skewing the results toward more of the kids they test being gifted. This is, of course, just my own conjecture.

I'd be curious to see if there were actual studies done separate from a self selected group like the GDC has.

eta: this is all anecdote as well, but this issue was discussed a few months ago here as well with various people chiming in as to their experiences with IQ similarity or variability among their own kids: http://giftedissues.davidsongifted.org/BB/ubbthreads.php/topics/142624/1.html

Is that the only place that stat comes from? If so, I'd have to agree with Cricket2--I'd hardly consider it reliable, for those reasons. Still, we do know that intelligence is highly heritable.

To the OP--I'd caution you to be careful about underestimating a second child who presents differently, First kids tend to have certain personality traits that align with a traditional concept of giftedness, and may tend towards more outward achievement, while laterborns may decide to take on different roles but be just as bright. Also, your second is very young. I have revised my estimates of my children's relative giftedness a fair bit over time, and may do so again.

I'll agree with ultramarina too as there is good indication that intelligence is pretty heritable, but genes are also pretty complex and most families have some variety in a lot of things from curly/straight hair and height (also fairly strongly heritable) to IQ. Depending on how diverse the genes coming into play are, there may be more or less variability among the family members.

Also, in agreeing w/ ultramarina, family roles and personality can certainly impact whether a child outwardly presents as gifted. My dd14 is more obvious about her giftedness than my dd12 due to a number of factors including a greater 2e thing going with dd12, personality, and perhaps other things.

I think the place that I read that 10 IQ point statistic is in Dr Ruf's 5 levels book. (I think I've heard her say it during one of her presentations also). I can't find my copy right now to check to be sure.

ultramarina - I totally agree with you about not underestimating my second child. That is why I wrote the post. (Maybe I just needed to hear someone say that my two kids can both be gifted but in different ways). My first experience with a gifted child is the one I've had with my first son. As I stated before, he is an overachieving perfectionist. My second son is just so much different from him, but still very bright.

Twins and Siblings: Concordance for School-Age Mental Development
Ronald S. Wilson
Child Development
Vol. 48, No. 1 (Mar., 1977), pp. 211-216


However, they also did some more in-depth analysis of twin-sibling sets (comparing a pair of twins with a non-twin sibling).

Wasn't there some research regarding the X chromosome and general intelligence recently?

Actually the GDC's standard is 13 points for 70% of siblings. According to them 100% is withing 30 points, unless you are dealing with 2E issues.

If one sibling is gifted the other is too. Not necessarily. If you have a MG child of 135IQ the sibling could be at 122IQ and not gifted. So at the lower ranges of the gifted scale maybe it is not so. I highly doubt though that if you have a PG child the sibling would be average although there could be 2E issues that would depress scores making it seem that way.

And I agree to not compare. Here is my story.

DS5.3 tested PG and has always seemed PG academically. H was copying books on the computer right after he turned 3 and started writing his own stories shortly after. Noone taught him how to spell, he just new. He has always gotten up in the morning and worked in his room writing. all he wants to do is write and learn. he past 2 months he has taught himself all about geography. He knows he name of every single country in the world looking at a map with no names of it. Learned about all the mountains, population, countries size etc. He is obsessed to say the least. He is doing long division and multiplication. It is ALL about academics.

Now jump to DS3.2. Although he loves books and could spend hours reading, ask me to do workbooks with him, reads easy sight word readers and knows some simple addition up to 10 he is no way near as interested and obsessed with it like his brother was/is.

The difference in the 2 is the thinking process. DS3's abstract thinking ability is remarkable, his attention to detail seen in various formats or just out and about. Both have always been very observant but DS3 is still more. An example, a couple of months ago DS3 was sitting staring at a picture and asked what something was. I said it is water. Like a beach, and water. He kept staring and asked but what was IN that water then. He gets very obsessed with things like this. DS5 was right there and I could see he looked at the picture clueless to why anybody would ask a question like that. I am sure something like that never crossed his mind.

So completely different children. We might have DS3 tested in a couple of years, or actually we will because of some of his sensory/emotional sensitivities. It will be interesting to see what the difference in IQ will be.

Maybe +/- 10 points is typical, but we're talking about children who are, by nature, exceptional, no?

You couldn't prove that rule by my family. I'm the third of four boys, and I got the "smart one" shingle hung around my neck pretty early on. Both of my older brothers had the opportunity to capture that one first, but nobody noticed anything unusual in them, nor in the one who came after me.

The younger one has some personality red-flags for being an unidentified giftie, though... and since at least two generations before us went completely under the radar (mom's story is a classic of underachieving rebellion), it's worth looking at.