In a respectful way, I tend to disagree.
You see diligence and practice implies decades of focused practice to attain a high level. While I 100% agree that diligence and practice is the best way to improve, how does one explain the 6 year old that can perform Mozart at professional levels in NY's Carnegie hall? How does it explain a 4 year old girl that can speak in 7 languages? There's been near ZERO time for them to practice and accumulate this info in a normal manner, which would take decades for others to reach.
The definition of genius is exceptional intellectual or creative power or other natural ability... there is no doubt that it exists.
As for the rest... you've caught my attention and I will look in to it!
Dear Jerry, sorry but I disagree, that you disagreed my counter-opinion!

More precisely, I simply do not believe the stories you've linked. There are on the internet millions of stories like those two, but I believe neither of them. My opinion is that all of them only some urbanlegend-like thing.
Of course, I do not deny that there are some young kids who're __seems__ exceptionally talented, because they're able to_do/make/produce(etc) something which is very hard/difficult for the most adults too. This is real, okay.
But I think (deeply believe!) that in those cases/situations the sad reality is one from the following possibilities, or rather (most likely!), something mixture from each of them:
—The fortunate/unfortunate (choose something based on your personal taste...) kid is forced to learn and practice everyday 8 or more hours, he/she has no any "free/off time" therefore no any chance to live a "normal" childhood. And this had been started right off when he/she was born.
—Simply, the kid has Asperger-syndrome. If you do not know what is that, feel free to ask me because I ALSO has that syndrome, so, in short ("nickname") I am an Aspie. And an Aspie, if (s)he has interest towards something, does exactly what I've described in the previous point, just doesn't need any pressure/forcing by parents because (s)he is forced by his/her own "internal main tune" to learn/practice that special field of science or Art. Of course, the progress is far more quick if (s)he has a good teacher, however it is absolutely not impossible to "develop" something "genius" just from his/her own. This actually happened in my life, too: I learned programming just from my own, because I wanted to have my "own" programming language, that is, to create a new programming language, without any "external" help! I never learned programming in any school. Everybody told me, my goal is perfectly impossible, programming languages are developed by serious teams, professors in Universities. Well, I DID! (MADE. Sorry, I do not know did or made is the correct word in English in this context, both are the same in my native tongue...) Now, all scripts in my computer are written in MY OWN programming language, I use it everyday, and works weel perfectly!
So, okay, you may say there are indeed "talent", talent is exist... okay, but only if you label the Asperger-syndrome as "talent", because that syndrome gives the extremely strong resolutenes/determination, therefore the necessary diligence to practice something years-long, without pause, and for that special goal to sacrifice EVERYTHING ELSE in the life!
—The miraculous results/achievements are made not by that allegedly "genius" kid, but mostly by his/her parents. This happened for example by the young Mozart... most of his young "soundtracks" are written by his father, we can say it with serious likelihood.
To the rest: if you have any question about the Carnivore Diet, do not hesitate to ask me! If you think it is too offtopic here, just write me a private message. Don't worry, I am absolutely not angry or anything like that if you not agree my opinion about "genius", "being talented" and so on!