[FONT="]I have to agree with the others, it's not a contradiction at all, it's from different perspectives, you have to keep in mind that four different men wrote the gospels (John, Matthew, Luke, and Mark). If you were to compare class notes among four different people, would any of them be the same? Only one of the men that wrote one of the four gospels were at the crucifixion, and that was the disciple whom Christ loved, John (John 19:25-27). As for the other three authors, they wrote through what they heard from the word of mouth.
If your friend really knows scripture all that well, show him Matthew 1:1-17, and then Luke 3:23-38. At first glance, they appear to be totally different, and that’s because… they are, but it's not that they contradict. Luke 3:23-38 is the Davidic genealogy of Christ's mother, Mary, and Matthew 1:1-17 is the Davidic genealogy of Joseph. With that in mind, you won’t find Mary listed, or any other female for that matter, listed throughout the genealogies, simply because the name of females were not permitted to be listed in the genealogical tables. With that said, Christ was still from the line of David, as prophecy foretold, but you have to first understand that David had several children (1 Chronicles 3:1-10), two of which that are key in these genealogies: Solomon, and Nathan (1 Chronicles 3:5). It was through the line of Solomon that Joseph was born, and it was through the line of Nathan that Mary was born, both being born through the line of David. [/FONT]