This is an interesting argument I found on Infidels.org. I would suggest visiting and reading much of what they post there. It's very enlightening..
In two places in the New Testament the genealogy of Jesus son of Mary is mentioned. MAT 1:6-16 and LUK 3:23-31. Each gives the ancestors of Joseph the CLAIMED husband of Mary and Step father of Jesus. The first one starts from Abraham(verse 2) all the way down to Jesus. The second one from Jesus all the way back to Adam. The only common name to these two lists between David and Jesus is JOSEPH, How can this be true? and also How can Jesus have a genealogy when all Muslims and most Christians believe that Jesus had/has no father?
It seems to me that God can't even get his own "sons" genealogy correct. If they can't get the supposed most important person to their faiths heritage correct, how can you trust that the rest of the bible is anything but fantasy?