Have Parenting Questions? Ask a Parenting Counselor for Answers
People are in a way preprogrammed biologically to want to spread their own genes (like the rest of the species)
What separates us form the rest though, is that we can make a decision not to procreate as well as to raise a child that does not share our genetic makeup.
It is how you feel emotionally about the child (if you believe that nurture is as important as nature) it may not be a big deal to just love a child for who they are (either your own or an adopted or through a sperm donor) People are endowed with the capacity to love and have the ability to teach others they come in contact with. If it is not as important for you that a child is not athletic (it may be a daughter that you have versus a boy), and if you believe that you and your girlfriend can provide a steady and loving family life, then it would not matter where the child "came from"