Ah well its the alleles on your genes. One of you wifes parents has two recessive genes and one has dominant. You wife carries a mix of both of these - but only the dominant shows. You too, carry the blue eyed gene but as the brown is dominant, that is what shows. There are several possible combinations of the genes which your son could contain, and he just happens to have got both the recessives of hair and eyes, giving him the Blonde hair Blue eye combination.
Can You Explain This? Son Has Blonde Hair, Blue Eyes. I Have Black Hair , Brown Eyes, Wife Has Brown Hair, Green Eyes, See Below.
It is like Sski says. You are both carrying the recessive gene for blonde hair and blue eyes and with your son, he got the recessive traits of the blonde and blue. My ex husband and I have two children--one who has very blonde hair and light blue eyes (my coloring and everyone in my family) and the other has brown hair and green eyes (my husband's and grandmother's coloring). You never know which genes will dominate.
It's not Your baby
You must carry the recessive jean for blue eyes as does your wife. He inherited both recessive genes.