Hair Controversy
From Code Wiki
Code Lyoko characters, like most Humans, have hair on their heads. But it has been proven by the show itself that some characters have very weird yet natural shades of hair. There are two strong examples of these: Aelita and Odd.
Aelita
Aelita has pink hair. It has been proven she has this naturally because her mother was pink-haired, yet her father, Franz Hopper, was not. If her mother dyed her hair, it would not have been passed down to her as a genetic trait, and therefore her mother must have had natural pink hair. Either that, or she dyes it herself to honor her mother.
It can also be proved to be naturally pink from the episode Just in Time. In the episode, Jeremie materializes a hair of Aelita's and it is pink. Since it was materialized from her DNA, it would not have been pink if it had been dyed.
Odd
Odd has a streak of purple hair in the middle of his spike of blond hair. This would almost have to be permanently dyed, explaining why the streak doesn't fade when he takes a shower/goes swimming/is almost drowned by X.A.N.A.
Other cases
Taelia and William also have very extreme shades of hair. Taelia has dark pink hair (which is why Jeremie mistook her for Aelita in The Girl of the Dreams), and William has very dark and unnatural black hair. Some say he dyed it, some don't.
In Season 4, adults with unnatural hair colors have shown up: Chris from the Subdigitals, Odd's mother, and William's mother (who appear in Opening Act, Bad Connection, and Down to Earth, respectively). Chris's hair is snow white, although it may be bleached. Odd's mother has mauve hair, and William's mother's hair is a dark turquoise. Also, the female candidate who was trying out for the Subdigitals' opening act in Crash Course has teal hair.
