NeoGAF member Pokemaniac has discovered that there are new settings on the Nintendo Account page after poking around the My Nintendo site. The user reports that there are now sections for User ID which would appear to be a login name and also child accounts. Interestingly, the User ID seems to be able to be changed freely. You can also make up to five child accounts for each Nintendo Account you have. They are described below.
What is an account for a child?
An account for a child is a Nintendo Account that allows users under 13 (and up to 17) years of age to use the Nintendo Account services.