Or so I think.
At Google's scale, I think it definitely makes sense to put the extra engineering effort in to comply with the law while the kid is too young.
On the other hand, I'd probably sign up as a 5 year old if it meant Google would collect less information from me and show fewer ads. Paid account?
So more accurately: A US Federal Law Made My Daughter Cry
It's even likely that they already have such a thing in place for debugging purposes.
http://en.wikipedia.org/wiki/Children%27s_Online_Privacy_Pro...
(Hint: the answer is there is no such part.)