The elders warned Kushina not to tell even her close friends, Sasukes mother knew about the birth and word got back to Sasuke's dad. Which leads me to believe that Tobi is Sasukes father, after all he has alot of power and knowledge of events that are behind the scenes in Konoha as he is the Uchiha leader but also the captain of konoha's has police force. As pointed out above when the kyubi attacked the village itachi is watching sasuke and his parents are missing. Those are major clues. Tobi has a very high level power to be able to manipulate the kyubi all by himself which would make it easy for him to manipulate other members of his clan. No one has seen Sasukes dads abilities so it is very possible. Also who was Sasukes father's father? Could be even related as far as izuna or Madaras blood. Sasukes dad killed narutos parents this will further add on to the hatred but unlike sasuke naruto can forgive sasuke because it was not their fault and naruto is on the same pain level of sasuke as he knows what it's like to have his parents killed and sasuke will see that naruto shares the same pains as he did and they can finally understand eachother.