I would also agree that the virgin birth is of some importance but for slightly different reasons. I am not convinced that either Matthew or Luke understood Jesus conception by the Holy Spirit as evidence or an argument for the ‘incarnation’ in the way we have traditionally understood it - ie. as the means by which the divine and human were combined in Jesus. (I think Danutz misses the point here as well in the comment he has justed posted: the manner of the conception is not presented as proof of Jesus’ divinity.) Rather they seem to connect it with a messianic expectation: it is a sign to Mary in particular that the child really will be both saviour and king of his people as the angel had promised (eg. Luke 1:34-35). The title ‘Son of God’ in Luke 1:35 is not the same as the later trinitarian formulation ‘God the Son’. The New Testament nowhere makes either the effectiveness of Jesus’ death or his ‘sinlessness’ dependent on the virgin birth in the way that NinjaHound suggests. See also these comments on Matt. 1:20-23.

Exactly in what sense Matthew understood Jesus conception by the Holy Spirit as a ‘fulfilment’ of Isaiah 7:14 is difficult to say, but I agree with Peter that the larger context in Isaiah 7-9 has to be taken into account. It is characteristic of the New Testament’s use of scripture that brief quotations or allusions bring whole narratives and arguments into play - they are not merely ‘prooftexts’ (see these comments). I think we could say in this case roughly that Matthew has borrowed Isaiah’s sign and reapplied it in order to make sense of the story that Joseph was not the father. But as Peter points out, the analogy does far more than simply support the belief in a virgin birth. Matthew transfers to Jesus a whole narrative about judgment and salvation and the inauguration of an utterly different type of rule in Israel. (It is interesting to note that in Isaiah the name ‘Immanuel’ is associated with judgment and destruction (7:14-17; 8:7-10) rather than with salvation and comfort.)

So, NinjaHound, you are right to draw attention to the problems posed by the Gospel accounts of Jesus’ conception. But before we start jumping up and down and blaming the Vatican for pulling the wool over our eyes, we should look more closely at what the Bible is actually saying.

Here’s a hermeneutical parable. Suppose you ask someone the way to the city of truth, and they say to you, ‘Follow this road, it will take you across a number of fast flowing rivers, and eventually you will come to the city of truth.’ So you travel along the road and you come to a bridge across a river. It’s a mighty fine bridge, though of a rather quaint and antiquated design - but as you start across it, you hear a horrible cracking noise and the bridge lurches violently, and you scramble back to the river bank. At that point you might say to yourself, forget it, I’m not going to risk my neck crossing that bridge, and you abandon your journey. But you also have the option of trying to repair the bridge, reinforce it, or even of knocking it down and starting again using a better methodology. Which is the better course of action?

I think that there are a number of flimsy bridges on the road to the city of truth at the moment - bridges that have fallen into disrepair, or were not well-constructed in the first place. Part of the task of an emerging theology may be to do that reconstructive work for the sake of others who follow.