Expert: Dana Krempels, Ph.D. - 11/28/2007

Question
me- i have blonde hair and blue eyes
mum - blonde hair and blue eyes
dad - mousy brown and blue eyes
grandma- blonde hair blue eyes

partner- dark brown hair and green/brown eyes
mum- auburn hair blue eyes
dad- dark brown hair brown eyes

Answer
Dear Katie,

Both hair and eye color in humans is controlled by more than one gene, and this makes it very difficult to accurately predict either one in a pairing.  However, since both you and your partner have light-colored eyes, it is likely that the baby also will have light-colored eyes.  If your partner has truly *brown* eyes, then there's about a 50% chance that the baby will have brown eyes, and a 50% chance that his/her eyes will be blue or green.

Dark hair is generally considered recessive to light hair, but it's more complex than that.  There are two types of human melanin, eumelanin (brown) and phaeomelanin (reddish).  Both are produced in some humans, and depending on what the genes encode as far as *amount* of pigment, the hair can be dark to light brown, sometimes with a reddish cast.

If your partner inherited his mother's phaeomelanin ability, then he might pass it on to his offspring.  But if the child also inherits his dark brown hair eumelanin deposition, the red might be masked, and the child will have dark brown hair.

*whew*!  Complicated!  But in short, if you have blonde hair and blue eyes, the baby's hair color will pretty much be determined by what your partner "donates" in the eye and hair color gene department, since you express the recessive conditions in both cases.  From what you've said, I'd guess there's about a 50% chance of light eyes, and a 50% chance of lighter/reddish hair versus darker brown hair.

Whatever happens, I hope the baby is healthy and lovely.

Good luck!

Dana