If Jesus did exist it is likely he was the son of this Joseph fellow, and I have heard many theories about him being Greek. That way, Jesus could be a Greek Jew (blood passes through the mother if I remember correctly).
Interesting.. I must look into that.
EDIT: Hay, there is a special on Investigation Discovery Channel right now, called "The Real Family of Jesus".
Did you know that Jospeh had children from another wife...Jesus' step brothers. Also, that the gosples point to John the Baptist being jesus' cousin.... Also, that Joseph died when Jesus was a kid, and him and his mother were destitute (in fact, he was not even allowed to attend the funeral because there were doubts about his "real father"...if ya get my drift). Its on right now, pretty neat stuff. 2 hour special.
If you get the ID channel, look for it, else maybe check around YouTube.
Man, wouldnt it be cool, if there was the same level of scholarly investigative programs dealing with Islam, and its origins.