This manuscript (which I have taken the liberty of translating to the best of my ability) is one I stumbled across at, of all places, Moody Library at Houston Baptist University. Across the page were scrawled the words "Can't let this get out".
Article 1. Whether marriage between two persons of the same sex is commended by God.
Objection 1. It seems that the marriage of two persons of the same sex is not commended by God for God explicitly commends marriage between two persons of opposite sex saying “Therefore does a man leave his father and his mother and cling to his wife” (Genesis 2:23) and this commendation is reiterated by Our Lord who said “For this cause a man shall leave father and mother and shall be joined fast to his wife” (Matthew 19:5) and was repeated too by Apostle who also said “For this reason a man shall leave his father and mother, and shall cling to his wife” (Ephesians 5:31).
Objection 2. Further, our forebears whose marriage was the first marriage were commanded to "be fruitful and multiply" (Genesis 1:28), and this command is understood to be applied to the whole of the human race, being descendants and therefore inheritors of that original command. But a marriage formed only by members of the same sex would be, by nature, incapable of honoring this command.
Objection 3. Further, the Apostle has explicitly condemned the sexual union of two members of the same sex saying of women “Thus God delivered them to the passions of disgrace; for even their females exchanged natural use for what is contrary to nature,” (Romans 1:27) and of men “And the males also, in the same way, abandoning natural use with the female, burned in their longing for one another, males performing shameful acts among males, and receiving in turn within themselves the requital benefiting their deviancy.” (Romans 1:27). And as a coupling from which sexual union is absent cannot be understood to be a marriage, there can be no marriage between members of the same sex.
On the contrary when people are joined in marriage they become one flesh (Genesis 2:24).
I answer that King David was married to multiple women, becoming one flesh with them. And we know that when two, though they seem disparate, are each equal to some third, they must also be one each with the other; for the Philosopher tells us that “when A belongs to B and C and is affirmed of nothing else, and B also belongs to all C, it is necessary that A and B should be convertible.” (Prior Analytics II,22,68) So if Ahinoam, Abigail, Maachah, Haggith, Abital, Eglah, Bath-Shua (1 Chronicles 3:1-6) and Michal also, who was barren, were each wives of King David and thus one flesh with him, they must also have been one flesh one with another. And inasmuch as becoming one flesh is marriage, Michal and Abigail were married one to another. Further we know that this relationship (of Abigail to her wife Michal or to any of her other wives) was not condemned by God for God sent the prophet Nathan to rebuke the King when David committed sin of a sexual and marital nature but God did not condemn King David for his becoming one flesh (and thereby joining in marriage one to another) with his wives, and we know that God does condemn that which is sexually immoral or adulterous for the writer of Hebrews tells us “Let marriage be honored by all, and the marriage bed undefiled” (Hebrews 13:4); for "God will judge the whoring and adulterous", and God did not judge the marriage union of Michal and Abigail or of any of David’s wives who did not commit adultery. Finally, in His own commentary on the uniting together of one flesh, our Lord informs us that the unification is one spiritually enacted by God, saying “So that they are no longer two, but one flesh. What therefore God joined together let no man separate” (Matthew 19:6) so that we are forbidden from separating that union—be it between members of the same or divers sexes—which the Lord has established, either in our proclamations or by action of man.
Reply to Objection 1. The Philosopher states that the predication of truth to one proposition is not, in itself, the denial of truth as predicate of another statement so long as the two statements are not logically opposite (De Interpretatione 7). When the Holy Scriptures affirm that “a man shall leave his father and mother and be united to his wife” (Genesis 2:23; Matthew 19:5; Ephesians 5:31) said affirmation is not contrary to but merely subcontrary to the possible statement that “a woman shall leave her father and mother and be united to her wife”. Conversely to affirm that a one flesh union may be established between two of the same sex is necessarily subcontrary, and not contrary to, the proposition that a one flesh union may be established between two of divers sexes. Thus in affirming one flesh union between persons of divers sexes neither Moses, nor Our Lord, nor the Apostle deny the possibility of one flesh unions between members of the same sex
Reply to Objection 2. The book of the prophet Samuel confirms Michal as a wife of David (1 Samuel 25:44) and we know that Michal is finally barren for the Holy Scripture tells us “Michal daughter of Saul had no children till her dying day.” Thus the fact of barrenness in a marriage can neither prevent nor annul the mystic one-flesh union. Furthermore, we know that God has supplied, by grace, a means for those who are barren to fulfill the command of Genesis to be fruitful and multiply for the prophet Isaiah proclaims “Of the eunuchs who keep My sabbath, and choose what I desire and hold fast to My covenant, I will give them in My house, and within My walls a marker and a name better than sons and daughters, an everlasting name will I give them that shall not be cut off” (Isaiah 56:4-5). But that which is better cannot be inferior to that which is worse so that the keeping and following of God’s will must be sufficient to fulfill the command that we should be fruitful and multiply. And this is commensurate with Our Lord’s declaration that all the law and the prophets depend on the two commandments that we are to love the Lord our God with all our heart and with all our soul and with all our reason and that we are to love our neighbor as ourselves (Matthew 22:37-40) and with the Apostles insistence that the second command: “You shall love your neighbor as yourself” sums up the Law. And that upon which a thing is dependent cannot be lesser than that on which depends upon it—on the contrary the dependent is the inferior. So by keeping the Law of God, by Loving God with all heart, soul, and reason, and by loving neighbor as themselves, couples which are by nature or by circumstance barren in terms of children are, in the eyes of God supremely fruitful in the multiplication of God’s love thereby fulfilling the commandment set to the first marriage. Further a marriage may nevertheless establish a union of one flesh and be blessed by God without sexual union for the Apostle admonishes the Corinthians “Do not deprive one another, except by common consent for an appropriate period, so that you might have leisure for prayer, and then come together again so that the Accuser might not test you through your inconstancy. Now I say this as a lenient concession, not as ordinance. I want all human beings to be just like me” (1 Corinthians 7:5-7) making clear that the command not to deprive one another is contingent on the inability of the couple to resist the Accuser in the absence of sexual intercourse one with another. But to those marriages in which is given the gift of celibacy to both members, so that they have leisure for prayer, what a grace is given by God and what joy to the Apostle.
Reply to Objection 3. To condemn one or more particular instances of an act is not thereby to condemn all instances of said act. When the Apostle condemns those unions of men with men and women with women, it is clear that he is condemning that which is contrary to nature and is resultant of adoring and worshipping creation rather than the Creator only (Romans 1:25). Further we know that God through the Apostle did not intend this condemnation to be universal in nature for further in the same discourse and as an example of the same surrendering by God to reprobation we see that some are defiant of parents (Romans 1:30). Yet Perpetua is commended by God with visions and comfort despite defiance of her father saying in her own account:
'Then, when it came my turn, my father appeared with my son, dragged me from the step, and said: ‘Perform the sacrifice--have pity on your baby!’
Hilarionus the governor, who had received his judicial powers as the successor of the late proconsul Minucius Timinianus, said to me: ‘Have pity on your father’s grey head; have pity on your infant son. Offer the sacrifice for the welfare of the emperors.’
‘I will not’, I retorted.
Are you a Christian?’ said Hilarianus.
And I said: ‘Yes I am.’
So we know that those actions described by the Apostle are not here, best understood as universal but as particular condemnations fitting only to particular circumstances as a result of particular and wilful blindness to the glory of God.
Further, we know that sexual intercourse in marriage is commended to us as a tactic for resisting the impassioned tempers and sexual incontinence foisted on us by our passions and by the Accuser, for the Apostle clearly tells us “But if they cannot remain continent, let them marry; for it is better to marry than to be afire” (1 Corinthians 7:9). But what help would this instruction be to those who are, in their own natures, attracted to members of their own sex rather than to those of a divers sex if marriage were limited to a union between those of divers sexes? It would be useless, and as we know that words from the mouth of God do not return empty but accomplish that which God desires (Isaiah 55:11) it is clear that this word--that it is better to marry than to be afire--is an exhortation establishing marriage as a refuge built for members of the same sex as much as for members of divers sexes.
