I dont think I disagree woth you at all Nawaki. I came to a similar conclusion when I watched Naruto and here are some points that suppot it. Ok first of all Naruto has the ability to do Rasengan which only the 4th and Jiraya can do (Kakashi can but not as strongly) which induces us to believe that it is a blood line limit. But if it then Jiraya would know that Naruto is the 4th's son so lets just assume thats its not. We can also believe that Tsunade at some level likes Jiraya, I mean cmon Saukura likes Naruto but she stills beats the crap outta him. If they did have an offspring (slighlt unlikely) it has to be the 4th. Now it is quite possible that the 4th had a son that his dad and mom never knew about cuz I mean Naruto's mom is still unknown. The thing that makes me want to believe that Naruto is Tsunade's grandson is how she reacts whenever Jiraya mentions the 4th and always looks a little sad as if she disaproves of him sacrificing his life for the village. And I mean Tsunade's brother does look like Naruto just with brown hair. The only thing thats stopping me form believeng that Naruto is Tsunade's grandson is that she deeply loved that other guy and that that would be too good to be true
Ok you can call me a loser for writing all this now
