>>18071512
>>18071520
Eye color is mainly determined by a single SNP in HERC2.
AA - brown
AG - most likely brown but can be green/hazel if you have some minor genes.
GG - blue or rarely light green.
AA+GG=AG
AG+GG=either AG or GG.
A man with brown eyes has a near to zero chance of having blue-eyed children with a blue-eyed woman if he is AA, and a 50% chance if he is AG.