The Father of Jesus (Matthew 1:18)

 
(1:18) "When ... Mary was espoused to Joseph, before they came together, she was found with child of the Holy Ghost." After listing the genealogy of Jesus, Matthew tells us that Joseph was not Jesus' father after all, which of course makes the entire genealogy meaningless. The Holy Ghost, not Joseph, was the one who impregnated Mary, contradicting many scriptures which clearly state that Joseph was the father of Jesus." - The skeptic's annotated bible

Answer: Jesus was the son of God born in the lineage of David and was born of Mary who was also a descendent of David. Jesus was the adopted son of Joseph since he was born of the Holy Spirit of the Virgin Mary.  As the adopted son of Joseph, he is the legal heir of Joseph and King David who inturn was the descendent of Abraham.