There's so many differences in the gospels about Jesus. One example in one account he's born during the life of Herod, in another he's born in the time of a Syrian governor who ordered a census it like a 12 year difference. This is just one of many discrepancies.
Christians will say things like what about the historians that say something about Jesus or Christ in their writings. Well for one the name Jesus is never mentioned or is Greek proper name just that of his title Christ. But is this the Christ their referring to? Many Christians don't realize that there was more then one god or deity with the title Christ. Serapis, Helios and others.