As many of you may know, Luke Skywalker has long, wavy golden blond hair (just like me). But as others of you may know, his parents, Padme and Anakin, both had darker brown hair. So how did Luke get his luscious locks? Did Anakin cheat on Padme? Did someone mix the real Luke with a blond boy on the way to Tatooine? Or was this just a mystery with the answer hidden in the depths of the Unknown Regions?
This is simply how genetics works in the real world. There is no other explanation needed.
"Brunettes Can Give Birth To Blondes (Single Recessive Genes)"