Most of the debate against homosexuality centers around six verses in the Bible. Yes, that is correct -- there are only six verses that explicitly deal with this question.
Two of those verses are in Leviticus (18.22 and 20.13), a part of the Levitical code that also prohibits eating crabs, clams and oysters as an abomination, among other things. Clearly, these verses were written to a cultural and religious context not our own.
The next two, Genesis 19.1-29 and Judges 19.1-30, are very similar. Genesis 19 is the story of Sodom and Judges 19 is clearly also based upon that text. In both stories, a mob of men seeks to rape a man who is visiting. In the Judges text, when that becomes impossible, they rape the man's female concubine instead. Once more, clearly this text is a condemnation of (gang) rape -- the gender of who is involved seems beside the point. We can read these stories and all agree that rape is heinous and wrong.
The remaining two are in the New Testament, both from Paul. In 1 Corinthians 6.9, Paul lists categories of sinners who will not inherit God's kingdom. He uses two specific Greek words that don't translate well to our culture: Malakos and aresenokoites. These words are used to describe a Greco-Roman system in which older men paid to have sex with younger men. The issue is paying for sex, particularly because this is almost always coercive to the one being paid. Once more, clearly wrong, not clearly a condemnation of all forms of same-sex activity.
Finally, there's Romans 1.18-29, a text in which Paul describes the fallenness of our world. He talks about those who have given up the Creator to worship the created, about women and men who gave up what was natural to engage in what was unnatural, something Paul describes as having sex with someone of the same sex. What's important to note here is Paul's description hinges upon two things: His understanding of what is "natural" and the giving up of oneself to sexual delight and experimentation.
Paul had no conception of homosexuality as a natural reality for a small percentage of the population. He didn't know what we know now, that some people are homosexual for reasons outside of their choices (likely a combination of genetics and hormones). He didn't know what we know now, that we also see homosexuality among a small percentage of the animal kingdom. He is writing about sexual experimentation and hedonism, about the choice to place the fulfillment of lust above all else.
Ironically enough, same-sex marriage is the most powerful answer to Paul's argument in Romans 1. Those who argue that homosexual persons should "change" and be straight are the ones insisting they should give up what is natural to them. Those who insist they should remain celibate are leaving homosexual persons in a tenuous state, one that (unless you have the spiritual gift to pull it off) means you will likely live a life of pain interspersed with unhealthy sexual experiences.
Rather, those who wish to get married are doing so precisely because they want to avoid the sin described in Romans 1. They don't want to turn from who they naturally are. They don't want to burn with lust and be tempted to make bad decisions. They want to do what Christians have historically believed is the best option for sexual expression -- enter into a life-long commitment that is disciplined and involves self-sacrifice.
That means I think same-sex marriage is actually an inherently, for Christians, conservative choice. In a culture that rarely respects marriage, where sex is far too often cheap, at best, and destructive, at worst, it simply boggles my mind that Christians would tell gay people not to get married. The Christian call to all people, gay or straight, is to live disciplined lives, where sexuality is experienced in a covenanted relationship, a place where it can be the avenue of grace that God intended it to be.
The only remaining question is whether marriage is indeed the proper avenue for gay Christians seeking that covenanted and disciplined commitment.
So the question remains, however, whether marriage is indeed the proper state, the best call to gay Christians. This question raises up an oft-overlooked verse in the debate. Though Jesus never chose to address the question of same-sex activity in any form, he did address the question of marriage. He says in Matthew 19, "Have you not read that the one who made them at the beginning 'made them male and female,' and said, 'For this reason a man shall leave his father and mother and be joined to his wife, and the two shall become one flesh?' So they are no longer two, but one flesh."
How does this text affect our understanding of same-sex relationships, particularly as they relate to the Christian teaching of marriage?
What Jesus is describing here is the primeval origin of marriage, what God had intended when he made the first two people back in Genesis 1-2. The original intent of marriage, at the beginning, was one man and one woman united for life. And the primary purpose of that relationship, as described in Genesis, was so a person would not be alone, but would have "a helper as his partner".
You might be catching that when Jesus references this ancient text, he is actually not primarily concerned about same-sex relationships, but rather with the question of divorce. Indeed, for conservative Christians who have embraced a more generous understanding of divorce, one that allows for remarriage as an experience of grace after that tragedy -- for those same Christians to use this text to reject same-sex relationships is one of the cheapest interpretive moves out there in contemporary Christianity.
Jesus' disagreement in Matthew 19 is with a system of divorce that had grown from the Mosaic code, one in which women had no choice but could simply be dismissed at will. This increasingly led to poverty, to the discarding of someone after a man was done with her. Jesus rejects this, insisting that just because the code allowed for divorce in our fallen world does not mean that people can be discarded. He insisted that the allowance of divorce does not change the original intention of marriage -- to wit, that it should be life-long, that it was focused on a self-giving care for the other.
Christians are people of grace -- people who, following Jesus, do not use the law to wound, but use the law of love to heal. For that reason, many contemporary Christians find no trouble agreeing with Jesus that discarding people is wrong, but still would say that if a divorce does happen -- always the tragedy of the death of a marriage due to innumerable sins -- those divorced people are not precluded from the grace of remarriage in the future.
Similarly, one of the original creation intents of marriage was for the procreation of children. However, some couples are not able to do that. Some choose not to do that. We don't forbid them from marriage. The vast majority of Christians also would not forbid them from the experience of sex within that marriage. One of the biggest reasons is because the actual creation intent that comes from God's own mouth is that marriage is so that a person is not alone, but that she or he can live a partnered life with another.
So, for people who, simply through the virtue of how they were created, are gay or lesbian ... what is the graced response? When it comes to divorced people and those who cannot (or choose not to) bear children, two groups who may not experience the full original intent of marriage in creation, they are still invited to marriage because of the deeper grace of a covenanted life with a partner. Will the church also share that grace with those who, because they are gay or lesbian, clearly cannot be united for life in a sexual union with someone of the opposite-sex, not without entering into a relationship that will wound much more than it will heal?
Jesus is teaching us about the intent of marriage -- not about the only possible way it can be experienced. For the church to be an avenue of grace in our world, it must offer the grace of marriage to LGBTQ people just the same as it does to those who are divorced, just the same as it does to those who are infertile or who choose not to have children.
Jesus also taught the legalists in his day that humans were not created for the law, but the law was created for humans (Mk 2.27). Jesus rejected those who took such a strict interpretation of the law that it wound up wounding those without power, tying burdens on people’s backs that were impossible to carry. He rejected religious leaders who would not try to lift those weights (Mt 23.4 and Lk 11.46). Jesus taught us that disciplined love is at the heart of who we are. And disciplined love does indeed call for all people in the church to have access to all of the sacraments -- including that of Holy Matrimony.