Toaru series. this is from Toaru Kagaku no Railgun S. it's the second season of the Railgun series, but i recommend that you watch Toaru Majutsu no Index 1 and 2 first, because it's the main series and things will probably make more sence

I disagree with you

Fullmetal Alchemist: Brotherhood

Or the original series, I personally like em both.

Here is a picture that will explain it in basic form. I'll go into more detail later. Basically if your parents each have one of the genes that are broken, their eye cannot create pigment and is blue, if they have opposite types of mutations, then they can have a child who can have normal brown eyes.

I'll try, but I'm running off my memory of year 12 human bio.
Eye colour is a polygenic trait, meaning that more than one gene effects your eye colour. Something like 8, I think it was. This is a simplification, but at each loci (Location of the gene) you can have two genes for darker eyes, two genes for lighter eyes or one gene for each. If you had two genes for lighter eyes at each one, you'd end up with nice blue eyes, and since you don't have the genes for darker eyes you can't pass them on. Ergo, if your partner also has light blue eyes, your kid can't have dark brown eyes because neither of you have the genes to pass on.
Jesus I feel like I'm reading simple English wikipedia. Hopefully I'm getting the idea across without either sounding like a dumbass or using too much jargon.

I posted a picture above that explains how blue eyes parents can have a brown eyed kid.

i was spelling it for phonetical purposes but you are correct. Anon not a troll for once.

and from experience if you say ore when you're a girl
you will be laughed at and they will comment about being a trap

The top is Toradora, and I think the bottom might be Zero no Tsukaima, although I'm not entirely sure about that one as I haven't seen ZnT.

Denpa teki na kanjo