Dear boy, do not be at all ashamed that you desire a girl, or that a girl longs for a boy, but see to it that it leads to marriage, and not to fornication. Then there is nothing disgraceful about it — as little as eating and drinking is a disgrace. Celibacy is supposed to be a virtue, but it is a veritable miracle of God, just as if a person did not eat or drink. It is beyond the capacity of a healthy body, not to mention the incapability of sinful and depraved human nature.
There are not many virgins to whom God granted a long life; rather hurriedly He whisked them out of this world, like Cecilia, Agnes, Lucia, Agatha, and others like them.
I know full well how noble that treasure is, but also how difficult it is to preserve for any length of time. If in every town, there were five boys and five girls, all twenty years of age, completely pure, with no experience of natural discharge, then I would be right in saying that the state of Christianity was better than in the days of the Apostles and martyrs.
O Lord God, I believe that unchastity would not have become so prevalent and spread in such a terrible way, if it had not been for this rule and vow of chastity [required of clergy and monastics]. What a Sodom and Gomorrah the devil has created through these rules and vows! How vulgar has he made this odd chastity, causing unspeakable anguish. No brothel stimulant is as dangerous as these rules and vows invented by the devil.
Furthermore, I say that those boys and girls who entered an order before they felt the stirrings of flesh and blood, that is, those who are fifteen or sixteen or twenty years of age, should be immediately released, if they so desire. Their vow after all is useless, just as if a child had taken it. Consecration is valueless in this case, nor does it matter whether he is a priest, a deacon, or has entered some other holy order. Those consecrations are frauds and have no validity in the eyes of God.
(Luther's Works, Vol. 52, p. 273)
In saying this I do not wish to disparage virginity, or entice anyone away from virginity into marriage. Let each one act as he is able, and as he feels it has been given to him by God. I simply wanted to check those scandalmongers who place marriage so far beneath virginity that they dare to say: "Even if the children should become holy, celibacy would still be better." One should not regard any estate as better in the sight of God than the estate of marriage. In a worldly sense celibacy is probably better, since it has fewer cares and anxieties. This is true, however, not for its own sake, but in order that the celibate may better be able to preach and care for God's Word, as St. Paul says in 1 Corinthians 7. It is God's Word and the preaching which make celibacy — such as that of Christ and of Paul — better than the estate of marriage. In itself, however, the celibate life is far inferior. . . .
He who would enter into wedlock as a Christian must not be ashamed of being poor and despised, and doing insignificant work. He should take satisfaction in this: first, that his status and occupation are pleasing to God; second, that God will most certainly provide for him if only he does his job to the best of his ability, and that, if he cannot be a squire or a prince, he is a manservant or a maidservant. . . .
To sum the matter up: whoever finds himself unsuited to the celibate life should see to it right away that he has something to do and to work at; then let him strike out in God's name and get married. A young man should marry at the age of twenty at the latest, a young woman at fifteen to eighteen; that's when they are still in good health and best suited for marriage. Let God worry about how they and their children are to be fed. God makes children; He will surely also feed them. Should He fail to exalt you and them here on earth, then take satisfaction in the fact that He has granted you a Christian marriage, and know that He will exalt you there; and be thankful to Him for His gifts and favors.
(Luther's Works, Vol. 45, pp. 46-49)