Side note: Also, the only reason Goku is so much stronger than Gohan or Goten is because he wants to be. Neither of his sons are interested in fighting the way full bloods are, and no fighting = not increase in power for them. Even with the new godly transformation that Goku got, we see that a half blood can match and even surpass that power in the case of future Trunks in the Goku Black arc. To say that Goku is stronger than Gohan is to miss the fact that Gohan doesn't actually care. If he did then we'd be watching a slightly different show. But the point of Gohan not being interested is to highlight the fact that Goku isn't a normal person, and having dominating power isn't the point of him/his character or what makes him/his character so good. His drive to top himself is the main idea. Gohan may have greater power and talent, but since drive is the main factor, Goku is left stronger. That's one of the main point of DB after Goku lost his first tournament and learned the lesson that would define his character forever.