In Romans 1, Paul is setting out his understanding of the human condition, suggesting that God's wrath is revealed against the wicked who suppress the truth. He is arguing that the Gentile world, though bereft of the revealed truth, have sufficient revelation in nature. Unfortunately, the Gentile world has chosen to ignore this testimony, and have created idols rather than worship the true God. As an example of this renunciation of truth, they have engaged in sexual behavior that is contrary to nature. It is this passage, that ultimately stands as the foundation for most Christian opposition to same-gender relationships.
This is the foundational passage for some Christians who would be otherwise open to full inclusion of homosexuals into the church (this is the view of Richard B. Hays).
24Therefore God gave them up in the lusts of their hearts to impurity, to the degrading of their bodies among themselves, 25because they exchanged the truth about God for a lie and worshipped and served the creature rather than the Creator, who is blessed for ever! Amen.26 For this reason God gave them up to degrading passions. Their women exchanged natural intercourse for unnatural, 27and in the same way also the men, giving up natural intercourse with women, were consumed with passion for one another. Men committed shameless acts with men and received in their own persons the due penalty for their error. (Romans 1:24-27 NRSV).
The question is, what does Paul mean here? And is this passage the key to our understanding of this issue?
One of the problems that faces us today, is that there is this gulf of cultural experience that separates us from the 1st century. What was considered "natural" 2000 years ago may not be so now, or at least what was contrary to nature was different. In this regard, I appreciate the thoughts of James McGrath. James is a bible scholar and knows his way around the text better than I do. He makes this point about shame and honor as it relates to the issue of same gender relationships. His interpretation makes a lot of sense to me. He writes:
If we look carefully at the language Paul uses, we notice that the terminology Paul uses for such intercourse not that of sin but that of shame and dishonor. Looking at the background to this language may help us understand why Paul could think of homosexuality as a punishment from God. Paul's viewpoint appears to be that homosexual intercourse is shameful and contrary to nature, and it is important to look to Paul's ancient historical-cultural context in determining what such language would mean to him and his readers. Our idea of "natural" intercourse more often has to do with "tab A fitting into slot B." In Paul's time, the thinking about nature, gender and intercourse was that men are by nature active and women by nature passive. What would seemed shameful in this ancient honor-shame cultural context was the transgressing of such gender roles, with men demeaning themselves by taking the passive female role, and conversely women taking on the active role which is by nature male.
In other words, if James is correct, Paul is working off the assumption that same gender sexual activity isn't sin, but it is a sign of punishment, for they are acting shamefully and dishonoring their bodies, by doing what is contrary to nature. What is contrary to nature is, according to this view, taking on sexual roles inappropriate to one's gender. Beyond that, as James points out the most common form of same-gender relationship in that era was pederasty -- as is depicted in the picture I took from his site. Note one person is bearded, the other is not.
