Question: 

Why does the genealogy of Christ go from Adam to Joseph, when Joseph was not the father of Jesus (The Holy Spirit conceived Christ)? 

Answer:

Actually, the genealogy in Luke goes through Joseph, but the genealogy of Jesus goes through Mary in Matthew.  That is what most scholars accept.  The reason for this is probably that Matthew was written primarily for a Jewish audience and Luke was written primarily for a Greek audience.  Of course, both books are for everyone, but scholars note the particular Jewishness of Matthew and Greekness of Luke.  The Jews considered anyone born of a Jewish mother to be a Jew.  Having a Jewish father did not necessarily make one a Jew.  Naturally, Jews were concerned with genealogy through the mother.  On the other hand, Greeks were not interested at all in genealogy through the mother.  Joseph was the adoptive father of Jesus and Luke chose to show his descent from Abraham and David through his father even though Joseph was not the actual biological father.  Matthew shows Jesus’ descent from Abraham and David through his mother.  If I understand it correctly, Jesus was descended from David on both sides–from his mother and from his father.  I will admit that from our Western perspective it is strange that Luke gives Jesus’ genealogy through a father who was not his biological father, but for the Greeks this was the only line of descent they were interested in.  Clearly, Luke was aware of the virgin birth of Jesus from reading Luke 2:4-7 (where Jesus is called the first born son of Mary, not of Joseph), but he does not emphasize this as strongly as Matthew, perhaps partially because of the Greek predilection to look at male lines of descent.  That is how I understand this question.

John Oakes, PhD