Daizenshuu 4 Page 72

Scholars point to the annotations on Page 72 that specifically mention "hybrid vigor." The text suggests that Human-Saiyan hybrids have a 106% higher rage response than pure Saiyans. This is the "smoking gun" often cited to prove why Gohan is more emotionally volatile—and potentially more powerful—than Goku during the Cell Saga.

Dragon Ball canon cosmology - Character Stats and Profiles Wiki daizenshuu 4 page 72