Completely untrue. He started as Ganondorf, leader of the Gerudo tribe. After taking possession of the Triforce of Power, he gained the ability to become Ganon, the physical demonic manifestation of his personality and desires. He is greedy and self-serving, wanting only to provide for his own being. Therefore, becoming a warthog-like monster fits his personality perfectly. He was born as Ganondorf, he earned the ability to become Ganon later.

Seriously, I have no idea where the hell you got that from. There's not a single game in the series that suggests what you just said.