Infidels.org calls a contradiction "Human vs. ghostly impregnation".
|“|| Acts 2:30 Therefore being a prophet, and knowing that God had sworn with an oath to him, that of the fruit of his loins, according to the flesh, he would raise up Christ to sit on his throne;
Matthew 1:18 Now the birth of Jesus Christ was on this wise: When as his mother Mary was espoused to Joseph, before they came together, she was found with child of the Holy Ghost.
Logically this is not a contradiction at all, since both can be true, Jesus could be the child of a human by the Holy Ghost. Both Mary and Joseph were descended from David (see Matthew 1 and Luke 3). Therefore, "child of the Holy Ghost" is simply additional detail. Furthermore, "child of the Holy Ghost" does not imply a Virgin Birth, as the Holy Ghost could design the child in the womb.
- Meritt, Jim (1992). A list of Biblical contradictions. Retrieved from http://www.infidels.org/library/modern/jim_meritt/bible-contradictions.html.