Son Gohan is also Son Goku's adoptive father in Akira Toriyama's comic series DragonBall.

(Due to Chinese naming conventions, Sr. and Jr. are not added to the names of Goku's father and Goku's son in the story. In this writeup, I mainly talk about Goku's father.)

During his youth, Gohan learns martial arts under Mutaito, along with his peer Mutenroshi (Master Roshi) and others. Both Mutaito and Mutenroshi die on different occasions upon performing a suicidal move called the Mafuba against Piccolo. The Mafuba involves trapping a person or a demon into an electronic rice cooker labelled with a written spell.

After becoming an elderly, Gohan discovers Goku who fell from the heavens in a space capsule, and decides to adopt him. At first, Goku is a violent Saiyan from planet Vegeta intent on the destruction of the human race, but becomes a "normal" child after Gohan tosses him off a cliff and gives him amnesia. Growing up in an isolated mountain, Goku learns manners and some martial arts from Gohan. Later, Gohan is killed by none other than Son Goku himself during one of Goku's full moon shapeshifting berserker rages. Goku doesn't remember his berserker rages, but later puts 1 and 1 together to figure out what really happened. After Gohan's death, Goku believes that Gohan's spirit resides in the four star dragon ball. The same four star dragon ball appears as a decoration on Goku's son Gohan's childhood hat.