Johann Sebastian Bach wasn't considered a musical child genius for some 300 years for sure.
It's different in the last years, because science, better the Bach Science has found out recently, that there is indication of a choral phantasy of Bach, which Johann Sebastian composed in his childhood. With that discovery real essentials in the Bach History would have to be changed, which probably wouldn't impress most of all Bach enthusiasts. Because this assumption will definitely get lost in the Bach history again like so many more. This little note has already started its way into oblivion. At least this find has become today's FAQ number fifty-six and so there is a small chance, that this knowledge will be transported from an actual and considerable Bach biographer into the future.