Hi I have a 17 year old son who is gifted and a 9 year daughter old who is also gifted they do not get a long... I know the age difference is hard with any child,but I am finding gifted children have heightened emotions and I'm sure hormones have something to do with it but I am in need of some advice anyone who has gone thru this or is going thru this
My son is very critical of everything she dose and she takes everything he says to heart and I mean everything and it will eat at her for days or weeks please HELP

I think you need to have a frank talk with your son about what he can say and what he should say. If he is NT, there is no reason he cannot police his words and be kinder. He is older, almost an adult, so the largest share of the responsibility of not hurting his sister is on him.

That doesn't mean you cannot help your daughter to learn not to take the things he says to heart. And if it helps her, can you think of some examples of what he was like at that age when you correct him?

My children are not as old as yours, my DSS is 9 and my DD is 2. but when dd was in diapers, he used to comment about how disgusting it was that she wore a diaper. Of course, she was too young to internalize it, but we did tell him that he was in diapers until he was 4, so he had no reason to call her disgusting when he experienced that phase of his life, as well. Hearing you defend her, and remind him that he was not always so perfect is a growth opportunity for them both... he learns a little bit about looking in a mirror before you criticize, and she learns that the big brother that she idolizes, but hurts her, went through the challenges that she did.

Can you give a specific example of one or two things your boy has said that have been hurtful? I think those would be easier to respond to than a general description of "critical," which could mean different things to different people.