Please, notice, I do not argue that someone should use QWERTY. I'm just trying to point that the strongest reason to prefer Dvorak maybe not a reason anymore. Maybe there are other reasons, I dont know. But it seems for me that people keep arguing about speed while all that discussion might be obsolete. They'd better to discuss other reasons.
> But how will your child feel when they're different than their friends and have to make special accommodations when using someone else's computer?
Accidently I wrote a wall of text answering to this. I'm sorry, it is one of my favorite topics: developmental psychology. The tl;dr version of it is: I wouldn't teach my child how to type at all.
Now the long version.
If children wanted to be different, than I would say them: it is all up to you, my children, if you need my blessing, you got it.
Look, a person get a desire to be different somewhere after 15 years old typically. Maybe some manage to develop to this point earlier, but I do not know about such a cases. Mostly they get to it after 15. Before that his difference from others would be either indifferent or annoying.
If you taught your child to use Dvorak while he was in a kindergarten, it would go as you planned up to a moment when you child hits puberty (~12yo). Before it the motivation of a child is built over her desire to be a good girl (or boy, gender doesn't matter). She was not interested in being like others or being different. After that the motivation is an approvement of her friends. It means that teen becomes obsessed of being like others, and her underdeveloped skills of using QWERTY might get on the way of it. What will follow? The same that follow everytime with every teen and her parent, teen will decide that her parent is crazy weird graybeard, that it is a shame to have such a parent, and the only way to deal with it is to hide parent and his weird habits from friends. It means to pretend that she prefer QWERTY, to use QWERTY always, and even to provoke parents by using QWERTY defiantly and by arguing that Dvorak is bad and causes pimples. If you allow her to provoke you, if you start argue, than you just prove her that she was right about your inability to accept new ideas.
It is not necessarily would go by this scenario, but it is completely plausible scenario. If you are going to teach your child to some uncommon habits, then you need to take into a consideration that it could end badly. May I suggest an other way to do it? Don't teach your child to use Dvorak. Don't teach your child to use QWERTY. Let him to be a bad typist for the first 15 years of his life, it would do him no harm. Teach him instead to play a piano -- it gives him meta-skills that could help to learn any keyboard layout. Teach him to play a piano and wait patiently. Watch for him, you need a moment when your child stops being a jerk who believes that his friends are smarter and more experienced than his parents. It can happen at 15 years old, or 17 years old, or even 20 years old. Personal differences are great here.
After that you a free to convince your kid to learn Dvorak. It might be not so hard as it looks. After ~15 yo teens like to work on themselves to become better and stronger. So it is completely possible to convience him to learn Dvorak even without a manipulation.
Moreover, after all that was said, I believe that it is a bad idea to teach child to type. He will not need his skill for 10+ years at least. So why to bother? It is like to teach child to read at 3 years old, to be able to brag about how bright child is. No one is interested that for a 3 year old it is very hard to learn to read, it would be much easier at 5-6 years old. No one is interested that 3 years old have other skills to develop, skills that are easier to learn at 3 years old and maybe impossible to learn at 5 years old. No one is interested that to learn how to read child needs to read, but if he was taught to read at 3 years old, than he wouldn't use his skill for 2-5 years when he would read his first book. He might lose the feeling of novelty, and the book reading would seem boring for him before he tried.
People obsessed with early development but do not bother to learn basics of developmental psychology and to develop their children for a sake of children, not for a sake of parents.