Wow, only one post and people are already after my head.
Ok, maybe I exaggerated about the genetic impossibility, sorry if I enraged someone over the Internet, especially knowing what serious business it is. It's just that it's not much of a common thing - blond hair with brown eyes. The other way around however, is more common. Black people and Asians with gray eyes are rarer than Europeans with the same, but there's a lot of them I assure you.
I just figure people's eye color depends on hair and skin color, because for example brown eyes are brown because of melanin. So it's more likely for an Asian or African to have brown eyes rather than gray. (Note: I call green, blue and other similar eye colors gray, because they all look gray in certain lighting.)
But anyway, back to comic discussion, it's nice that Dora grows her natural color out. I think dying your hair is like putting colored lenses on or like changing your name - you're just trying to escape who you really are. But it's gonna be hard to get used to after 1300 strips of black-haired Dora.