Quote Originally Posted by Psyke
Ah I see, my bad I misunderstood Yukimura. Now that really does make Nauto look bad, doesn't it?
The 4th's wife was a drug-attic and alcoholic. He knew before hand his son would be a complete idiot when he was born so therefore he sealed the 9-tails inside of Naruto so he can have some sort of power to make up for his disability.