The reality of the Virgin Birth has been affirmed by the church at least as far back as when the Gospels of Matthew and Luke were written. It is affirmed in the Church’s earliest creedal affirmation, The Old Roman Symbol (or the Roman Baptismal Creed), dating from no later than the second century (during which time it is cited by both Tertullian and Irenaeus).
The only real debate in which the virgin birth played a central role was the translation of Isaiah 7:14 by the RSV (Revised Standard Version) in 1952. The translators rendered the Hebrew term alma (עַלְמָה) as “young woman.” Conservatives railed against the translation as trying to discredit the virgin birth. But in point of fact, while the term may refer to a virgin, that is not a necessary nuance of alma. When the translators of the RSV translated the Matthean passage citing Isaiah 7:14, Matthew chose the Greek term parthenos (παρθένος), which does mean virgin. Clearly Matthew understood the conception of Christ to have been both virginal and a divine miracle.
The fact of the virgin birth is key in understanding the importance afforded Mary in both the Catholic and Orthodox communions. The Catholic Church has taught the immaculate conception of Mary (that she was born without original sin) to further theologically guard the sinlessness of Jesus, i.e., that he was born into unfallen Adamic humanity. While Protestants have eschewed the Immaculate Conception, they too have asserted that Jesus inherited unfallen humanity from his mother.
In general, throughout the centuries, only pagan critics of Christianity and rationalists have denied that Jesus was born of Mary without a human father. Discussions of the virgin birth over the past two centuries have fallen largely in the realm of apologetic defenses of its reality.
For example, Charles Briggs (who, in 1893, was convicted by the Northern Presbyterian Church of denying inerrancy) saw the virgin birth as a touchstone doctrine, the denial of which put one on the proverbial “slippery slope” towards theological apostasy.
It is not merely the virgin birth that is in question, in the interest of the more complete humanity of our Lord; it is also the doctrine of original sin and the sinlessness of Jesus; it is also his bodily resurrection and ascension. . . It is the whole nature of the atonement and Christian salvation with the doctrine of sacrifice and propitiation. All these doctrines are hanging in the balance in those minds which doubt or deny the virgin birth. Those who give up the virgin birth will be compelled by logical and irresistible impulse eventually to give up all of these. 
Indeed, Briggs desired to have A. C. McGiffert, his former student and later President of Union Seminary New York, fired from his post at Union for denying the Virgin Birth.
During the 1930s, J. Gresham Machen published his magisterial The Virgin Birth of Christ, a volume that has never been equaled in comprehensiveness and scholarship on the topic. It too was apologetic in nature.
During the era of the Fundamentalist-Modernist controversy, the Virgin Birth attained a quasi-official touchstone status as one of the five fundamentals of the faith. The rationale was that accepting the virgin birth was a quick and easy test to see if someone believed in miracles.
Surprisingly, despite its professed importance as being foundational to the Christian faith, relatively little profound theological reflection has taken place regarding the virgin birth. In fact, prominent evangelical theologian Millard Erickson (who does accept the truth of the virgin birth) denies its necessity, as does Wayne Grudem (who also accepts the doctrine), to name just two. Erickson says,
But, we must ask, is not the virgin birth important in some more specific way? Some have argued that the doctrine is indispensable to the incarnation. Without the virgin birth there would have been no union of God and man.38If Jesus had been simply the product of a normal sexual union of man and woman, he would have been only a human being, not a God-man. But is this really true? Could he not have been God and a man if he had had two human parents, or none? Just as Adam was created directly by God, so Jesus could also have been a direct special creation. And accordingly, it should have been possible for Jesus to have two human parents and to have been fully the God-man nonetheless. To insist that having a human male parent would have excluded the possibility of deity smacks of Apollinarianism, according to which the divine Logos took the place of one of the normal components of human nature (the soul). But Jesus was fully human, including everything that both a male and a female parent would ordinarily contribute. In addition, there was the element of deity. What God did was to supply, by a special creation, both the human component ordinarily contributed by the male (and thus we have the virgin birth) and, in addition, a divine factor (and thus we have the incarnation). The virgin birth requires only that a normal human being was brought into existence without a human male parent. This could have occurred without an incarnation, and there could have been an incarnation without a virgin birth. Some have called the latter concept “instant adoptionism,” since presumably the human involved would have existed on his own apart from the addition of the divine nature. The point here, however is that, with the incarnation occurring at the moment of conception or birth, there would never have been a moment when Jesus was not both fully human and fully divine. In other words, his being both divine and human did not depend on the virgin birth Continue Reading →