If I wanted to bring up my biology degree for a moment for some Tin Man meta...
(and bear with me while I wax philosophic)
So, in humans, blue eyes are a recessive trait (b), while brown eyes (B) are dominant. That means that both parents have to have at least one blue eye gene (b) for their child to have blue eyes. As brown eyes are dominant (B), a parent who has both a blue eye gene (b) and a brown eye gene (B) in their chromosomes (Bb) will display brown eyes, but could pass on the blue eye gene to their children.
A blue-eyed parent would have two blue eye recessive genes (bb) and would have to pass on the blue eye gene to their offspring.
Only if both parents pass on a blue eye gene will the child have blue eyes.
yea yeah, get to the point
So two blue eye parents are by nature (bb)x(bb). It is not possible for two blue-eyed parents to have a brown eyed child (Bb or BB).
You were talking Tin Man?
Lavender Eyes/Queen had blueish eyes (bb)
Ahamo had blue eyes (bb)
DG has blue eyes (bb)
Alzadellia has brown eyes (Bb)
Ergo, Azkadelia had a different daddy...
Oh, could you imagine the fic on that one?
Yes, I know, it's a tv show and it's just casting of actors, but it's all about potential, baby.