That isn’t entirely true. Let’s
examine some of the teachings of the founder of the Protestants:
Luther most certainly did hold to Mary’s perpetual virginity, he did not view it as an article of faith that must be adhered to in order to be in union with the Church as the modern Roman dogma contests.
“Scripture does not quibble or speak about the virginity of Mary after the birth of Christ, a matter about which the hypocrites are greatly concerned, as if it were something of the utmost importance on which our whole salvation depended. Actually, we should be satisfied simply to hold that she remained a virgin after the birth of Christ because Scripture does not state or indicate that she later lost her virginity… But the Scripture stops with this, that she was a virgin before and at the birth of Christ; for up to this point God had need of her virginity in order to give us the promised blessed seed without sin (Martin Luther, Luther’s Works, 45: 205-206).”
“Now just take a look at the perverse lauders of the mother of God. If you ask them why they hold so strongly to the virginity of Mary, they truly could not say. These stupid idolators do nothing more than to glorify only the mother of God; they extol her for her virginity and practically make a false deity of her. But Scripture does not praise this virginity at all for the sake of the mother; neither was she saved on account of her virginity. Indeed, cursed be this and every other virginity if it exists for its own sake, and accomplishes nothing better than its own profit and praise (Martin Luther, Luther’s Works, 45: 205-206).”
As with Mary’s perpetual virginity, he also held to the Immaculate Conception, but again, not as an article which must be held to for salvation’s sake or for unity with the Church,
“The Roman church along with the general council at Basel and almost with the whole church feels that the Holy Virgin was conceived without sin. Yet those who hold the opposite opinion should not be considered heretics, since their opinion has not been disproved (Martin Luther, Luther’s Works, 31:173).”
“In regard to the conception of our Lady [the papacy has] admitted that, since this article is not necessary to salvation, it is neither heresy nor error when some hold that she was conceived in sin, although in this case council, pope, and the majority hold a different view (Martin Luther, Luther’s Works, 32: 79-80).”
By the end of his career, his position had changed. In 1544, Luther rejected the idea that "through the centuries a pure strain (massa imperdita) had been preserved from which Christ ultimately came. In his lectures on Gen. 38:1-5 he calls attention to the immorality and incest to be found among our Lord’s ancestors according to the flesh. (Martin Luther, What Luther Says, Vol. 1, ed. Ewald Martin Plass, St Louis: Concordia Publishing House, 1959, 151. This is the editors comment.)
Rather than long treatises on the subject, Luther again shifts the emphasis from the mother to the Messiah. Rather than discussing Mary’s sinlessness, he insisted Christ’s sinlessness was due entirely to the miraculous work of the Holy Spirit during conception. In 1532 he preached:
“Mother Mary, like us, was born in sin of sinful parents, but the Holy Spirit covered her, sanctified and purified her so that this child was born of flesh and blood, but not with sinful flesh and blood. The Holy Spirit permitted the Virgin Mary to remain a true, natural human being of flesh and blood, just as we. However, he warded off sin from her flesh and blood so that she became the mother of a pure child, not poisoned by sin as we are…For in that moment when she conceived, she was a holy mother filled with the Holy Spirit and her fruit is a holy pure fruit, at once God and truly man, in one person (Martin Luther, Sermons of Martin Luther, Vol. 3, ed. John Nicholas Lenker, Grand Rapids: Baker Books, 1996, 291).”