Expert: Dana Krempels, Ph.D. - 2/17/2008

Question
hi

Myself and my wife are thinking about having a baby and i just had a few questions about genes. My hair is medium/dark brown and i am tanned, my wife has dark brown hair but it has red/auburn/ginger tones and she is dark and tanned but with frekles. I have blue eyes and she has green. Her father had black hair (was spanish) and mother had red hair (scottish).

what hair color/skin type can i expect our baby(s) to have? thnx! :)

Answer
Dear Rex,

I wish I could help you predict what your baby's coloring will be.  But in the case of hair color and eye color, each trait is controlled by *multiple* genes, not just one each. That means that different combinations of whatever you and your wife carry can recombine in surprising ways.  If you have any blonde-hair genes in your heritage, and both of you carry them, then the baby could even be blonde.  But it's not possible to know in advance if you carry those, because the genes coding for darker hair mask the expression of blonde.

Humans produce two types of melanin (pigment responsible for hair and skin color):  eumelanin (brown) and phaeomelanin (reddish).  Your wife appears to express both types of melanin, so if she passes the phaeomelanin-producing genes to your child, the child might have reddish hair.  But your wife might not pass those on.  There's just no way to know in advance when you're dealing with a polygenic (i.e., controlled by several genes) trait.

Skin color is the same.  Some estimates suggest that there are as many as 10 genes affecting skin color (freckles are dominant, but there's no guarantee your wife has only freckle genes to give the child), and they combine to create a wide palette of skin tones.  So whatever combination your child inherits will determine skin tone.  Since you and your wife both have medium-tone skin, this could range from quite pale to quite dark, depending on which genes the child gets.

If you would like a very detailed excursion into the wonders of human skin color genetics, you can find one here:

http://0-biology.plosjournals.org.ilsprod.lib.neu.edu/perlserv/?SESSID=55da2f010...

I know this is confusing, but the short answer is:  there's no way to predict this.  But whatever color the baby is, I hope s/he's happy and healthy!

Good luck!

Dana