I think we are dealing with such a wide spectrum of genetic disorder here that one word doesn't describe all.
If the disorder (in itself a negative word, but that's what it is) causes severe medical problems, leading to early death, as with CF and MD, then 'different' is so inadequate as to be almost insulting. There are no positives in such a situation, except that the child is still here. Children are used to the concept of bodies going wrong, something the matter with some part or other, needing medicine or an operation to put it right.
As someone upthread said, they are on the verge of a breakthrough for CF and also MD, using gene therapy. So it is possible not only to say that something is wrong, but to hold out the hope of being able to make it right.
i can completely understand why De We's daughter doesn't want to be described as 'different'.
Wiv I don't know why you conflate geneticist with 'eugenics', with all its nazi connotations. For the life of me, I can't see why a world where no one had to suffer from CF, MD, sickle cell, Huntingdon's, even some forms of cancer, wouldn't be a good thing. Which is not to say, of course, that everyone currently suffering from those conditions should not be treated with the utmost love and respect.