Akira Toriyama's last anime

[Amadeus]

Personally, I think he ment for Gohan to have sort of a talent which he had thanks to his father. I don`t think he ment it to be a specific power-up or anything as such. I guess he developed it later on.

EDIT: And btw, the main protagonists of Dragonball are based off the main characters of the traditional Chinese novel Journey to the West.