He is not my favorite Church Father, nor do I really consider him as a Church Father…but that is another story. Coming from Palestine, his take on this matter is still of some importance.
And hear again how Isaiah in express words foretold that He should be born of a virgin; for he spoke thus: “Behold, a virgin shall conceive, and bring forth a son, and they shall say for His name, ‘God with us.’ ” For things which were incredible and seemed impossible with men, these God predicted by the Spirit of prophecy as about to come to pass, in order that, when they came to pass, there might be no unbelief, but faith, because of their prediction. … This, then, “Behold, a virgin shall conceive,” signifies that a virgin should conceive without intercourse. For if she had had intercourse with any one whatever, she was no longer a virgin; but the power of God having come upon the virgin, overshadowed her, and caused her while yet a virgin to conceive. … It is wrong, therefore, to understand the Spirit and the power of God as anything else than the Word, who is also the first-born of God, as the foresaid prophet Moses declared; and it was this which, when it came upon the virgin and overshadowed her, caused her to conceive, not by intercourse, but by power. (Ch. 33)
Dialogue with Trypho
Now it is evident to all, that in the race of Abraham according to the flesh no one has been born of a virgin, or is said to have been born , save this our Christ. But since you and your teachers venture to affirm that in the prophecy of Isaiah it is not said, ‘Behold, the virgin shall conceive,’ but, ‘Behold, the young woman shall conceive, and bear a son;’ and you explain the prophecy as if to Hezekiah, who was your king, I shall endeavour to discuss shortly this point in opposition to you, and to show that reference is made to Him who is acknowledged by us as Christ. (Ch. 43)
“Moreover, the prophecy, ‘Behold, the virgin shall conceive, and bear a son,’ was uttered respecting Him. For if He to whom Isaiah referred was not to be begotten of a virgin, of whom did the Holy Spirit declare, ‘Behold, the Lord Himself shall give us a sign: behold, the virgin shall conceive, and bear a son?’ For if He also were to be begotten of sexual intercourse, like all other first-born sons, why did God say that He would give a sign which is not common to all the first-born sons? But that which is truly a sign, and which was to be made trustworthy to mankind,—namely, that the first-begotten of all creation should become incarnate by the Virgin’s womb, and be a child,—this he anticipated by the Spirit of prophecy, and predicted it, as I have repeated to you, in various ways; in order that, when the event should take place, it might be known as the operation of the power and will of the Maker of all things. (Ch. 84)
Fragments of the Lost Work of Justin on the Resurrection
And we see men also keeping themselves virgins, some from the first, and some from a certain time; so that by their means, marriage, made lawless through lust, is destroyed. And we find that some even of the lower animals, though possessed of wombs, do not bear, such as the mule; and the male mules do not beget their kind. So that both in the case of men and the irrational animals we can see sexual intercourse abolished; and this, too, before the future world. And our Lord Jesus Christ was born of a virgin, for no other reason than that He might destroy the begetting by lawless desire, and might show to the ruler that the formation of man was possible to God without human intervention. And when He had been born, and had submitted to the other conditions of the flesh,—I mean food, drink, and clothing,—this one condition only of discharging the sexual function He did not submit to; for, regarding the desires of the flesh, He accepted some as necessary, while others, which were unnecessary, He did not submit to. For if the flesh were deprived of food, drink, and clothing, it would be destroyed; but being deprived of lawless desire, it suffers no harm. And at the same time He foretold that, in the future world, sexual intercourse should be done away with; as He says, “The children of this world marry, and are given in marriage; but the children of the world to come neither marry nor are given in marriage, but shall be like the angels in heaven.” Let not, then, those that are unbelieving marvel, if in the world to come He do away with those acts of our fleshly members which even in this present life are abolished. (Ch. 3)