Does it really matter if all of the new testament is 100% historically true? It can't all be true, the gospels contradict one another on many points, however it does not diminish the message.
So what if a tomb as a 1 in 600 chance of being Jesus'? So what if Jesus married and had a son? Does it change the message of Christianity so much?
Plato was a man. Einstein was a man. Buddha was a man. Kano Jigoro was a man. They all died, yet the message they carried remains despite their failings as men, or the crazy untrue stories attributed to them.
Why is it that certain religions take the obvious falsehoods of their faith as absolute truth? You apply reason and logic to all other problems, but go completely hands off when it comes to your religion. Christ did not ascend, body and all, to heaven. Christ did not rise from the dead. (Really if you were going to rise from the dead and wanted everybody to know about it, would you only appear to your best friends? NO! You would walk up the Senate steps in the Forum in Rome and give the Emperor a kiss on the head. If Christ did appear only to his best friends, and expected is message to get out, then I give him zero style points.) There was no world wide flood that wiped out all of the creatures on earth. We are not all the descendants from Noah. God did not get angry when someone shot an arrow from the Tower of Babble.
The message is important, not the fantasy around it.