From St. Gregory of Nyssa, On the Making of Man
Now the resurrection promises us nothing else than the restoration of the fallen to their ancient state; for the grace we look for is a certain return to the first life, bringing back again to Paradise him who was cast out from it. If then the life of those restored is closely related to that of the angels, it is clear that the life before the transgression was a kind of angelic life, and hence also our return to the ancient condition of our life is compared to the angels. Yet while, as has been said, there is no marriage among them, the armies of the angels are in countless myriads; for so Daniel declared in his visions: so, in the same way, if there had not come upon us as the result of sin a change for the worse, and removal from equality with the angels, neither should we have needed marriage that we might multiply; but whatever the mode of increase in the angelic nature is (unspeakable and inconceivable by human conjectures, except that it assuredly exists), it would have operated also in the case of men, who were "made a little lower than the angels ," to increase mankind to the measure determined by its Maker.
From St. John Chrysostom, On Virginity
When he was created, Adam remained in paradise, and there was no question of marriage. He needed a helper and a helper was provided for him. But even then marriage did not seem to be necessary... Desire for sexual intercourse and conception and the pangs and childbirth and every form of corruption were alien to their soul.
From St. John Damascene, An Exact Exposition of the Orthodox Faith
Carnal men abuse virginity , and the pleasure-loving bring forward the following verse in proof, Cursed be every one that raises not up seed in Israel. But we, made confident by God the Word that was made flesh of the Virgin, answer that virginity was implanted in man's nature from above and in the beginning. For man was formed of virgin soil. From Adam alone was Eve created. In Paradise virginity held sway. Indeed, Divine Scripture tells that both Adam and Eve were naked and were not ashamed. But after their transgression they knew that they were naked, and in their shame they sewed aprons for themselves. And when, after the transgression, Adam heard, dust you are and unto dust shall you return , when death entered into the world by reason of the transgression, then Adam knew Eve his wife, and she conceived and bare seed. So that to prevent the wearing out and destruction of the race by death, marriage was devised that the race of men may be preserved through the procreation of children.
But they will perhaps ask, what then is the meaning of “male and female,” and “Be fruitful and multiply?” In answer we shall say that “Be fruitful and multiply ”does not altogether refer to the multiplying by the marriage connection. For God had power to multiply the race also in different ways, if they kept the precept unbroken to the end. But God, Who knows all things before they have existence, knowing in His foreknowledge that they would fall into transgression in the future and be condemned to death, anticipated this and made “male and female,” and bade them “be fruitful and multiply.” Let us, then, proceed on our way and see the glories of virginity: and this also includes chastity.
From St. Maximus the Confessor, Difficulty 41
In order to bring about the union of everything with God as its cause, the human person begins first of all with its own division, and then, ascending through the intermediate steps by order and rank, it reaches the end of its high ascent, which passes through all things in search of unity, to God, in whom there is no division. It accomplishes this by shaking off every natural property of sexual differentiation into male and female by the most dispassionate relationship to divine virtue. This sexual differentiation clearly depends in no way on the primordial reason behind the divine purpose concerning human generation. Thus it is shown to be and becomes simply a human person in accordance with the divine purpose, no longer divided by being called male or female. It is no longer separated as it is now into parts, and it achieves this through the perfect knowledge, as I said, of its own logos, in accordance with what it is. Then, by a way of life proper and fitting to the Saints, the human person unites paradise and the inhabited world to make one earth, no longer is it experienced as divided according to the difference of its parts, but rather is gathered together, since no introduction at all of partition is allowed. Then, through a life identical in every way through virtue with that of the angels, so far as is possible to human beings, the human person unites heaven and earth, making the whole of creation perceived through the senses one with itself and undivided.
Another passage from the same work:
Indeed being in himself the universal union of all, he [Christ] has started with our division and become the perfect human being, having from us, on our account, and in accordance with our nature, everything that we are and lacking nothing, apart from sin (Heb 4:15), and having no need of the natural intercourse of marriage. In this way he showed, I think, that there was perhaps another way, foreknown by God, for human beings to increase, if the first human being had kept the commandment and had not cast himself down to an animal state by abusing his natural powers. Thus God-made-man has done away with the difference and division of nature into male and female, which human nature in no way needed for generation, as some hold, and without which it would have perhaps been possible
From Saint Gregory Palamas, Homily 43 "On the Gospel Reading for the Seventeenth Sunday of Matthew About the Canaanite Woman"
What is the starting point of our coming into the world? Is it not almost the same as for irrational animals? Actually it is worse, because the procreation of animals did not originate from sin, whereas in our case it was disobedience that brought in marriage. That is why we receive regeneration through holy baptism, which cuts away the veil which covers us from our conception. For although marriage, as a concession from God, is blameless, yet our nature still bears the tokens of blameworthy events. For that reason one of our holy theologians calls human procreation, "nocturnal, servile, and subject to passion", and before him David said, "I was shapen in iniquity; and in sin did my mother conceive me" (Ps. 51:5)
And another passage from Homily 14, "On the Annunciation"
God sent the archangel to a virgin and made her, who continued a virgin, His mother by means of a salutation alone. If He had been conceived from seed, He would not have been a new man, nor sinless, nor the Saviour of sinners. The flesh's impulse to reproduce is not subject to our minds, which God has appointed to govern us, and is not entirely without sin. That is why David said, "I was shapen in iniquity; and in sin did my mother conceive me" (Ps. 51:5). So if the conception of God had been from seed, He would not have been a new man, nor the author of new life which will never grow old. If He were from the old stock and inherited its sin, He would not have been able to bear within Himself the fullness of the incorruptible Godhead or to make His flesh an inexhaustible source of sanctification, able to wash away even the defilement of our First Parents by its abundant power, and sufficient to sanctify all who came after them.