I don't get nearly as far as you into these discussions with Eddie and Matt because I'd set the discussion up from a different foundation. I think nearly all of us agree that the historical Jesus is no more than a fragmented narrative that covered three years of his biological life. Some wouldn't even give us the three years.
Relying not only on those fragments, but other writings from the early Christian church, a council was formed to build a theologically coherent Christianity consistent with earlier pre Christ sources. Such a foundation almost demanded controversy--and we've had controversy ever since.
We believe in the virgin birth for theological reasons: with any other reasons we'd need a theological rewrite--and even more controversy. As things stand, it makes theological sense.