Trunks, also known as Trunks Brief, is a fictional character in the Dragon Ball franchise created by Akira Toriyama. Trunks is the son of Vegeta, a powerful Saiyan warrior, and Bulma, a human scientist. Trunks is known for his distinctive purple hair, which is a result of his genetic makeup as a hybrid of a Saiyan and a human.

Saiyans are a race of extraterrestrial beings that possess superhuman strength and the ability to transform into powerful, monstrous forms known as Great Apes. In their Great Ape form, Saiyans have purple fur, which is a result of the high concentration of melanin in their bodies. When Trunks was born, he inherited some of these genetic traits from his father, including the ability to transform into a Great Ape. However, Trunks’ human genetics also played a role in his appearance, including the color of his hair.

Trunks’ purple hair is also a result of his unique genetic makeup as a hybrid of a Saiyan and a human. In the Dragon Ball universe, hybrid offspring are often depicted with traits that are a combination of those of their parents. In Trunks’ case, his hair color is a combination of his father’s purple Great Ape fur and his mother’s human genetics, resulting in the distinctive purple color of his hair.

In conclusion, Trunks has purple hair due to his genetic makeup as a hybrid of a Saiyan and a human. His purple hair is a result of the combination of his father’s purple Great Ape fur and his mother’s human genetics, as well as the unique traits that are often present in hybrid offspring in the Dragon Ball universe.