Genes

In looking at my daughter it is amazing how genes work.  My husband and I both have blond hair.  If we get one allele from each parent then our daughter was destined to have blond hair as well.  If we look at my cousin and her family she and her husband both have brown hair.  They have three children, two boys and one girl.  You can definitely tell that they boy are her kids because they look just like her.  The boys both have brown hair yet their daughter has blond hair.  This leads us to believe that both parents are carriers of the dominant gene for dark hair (brown) and the recessive gene for light hair (blond).  This means that they have a 75% chance of their child having brown hair (the two boys) and only a 25% chance of having a child with blond hair (the girl).  If they were to have another child they would have a better chance of that child having brown hair than blond.  As we further our stud of genes and our understanding of the genetic make up of humans the more we know about our offspring.  At some point way into the future we may even be able to decide for ourselves what our children will look like.  We may be able to pick not only hair color but eye color and other physical features.