Nature in Romans
Verses 26 and 27 of Romans 1 are often quoted by people who think that the Bible teaches that same-sex relationships are wrong.
For this cause God gave them up unto vile affections: for even their women did change the natural use into that which is against nature: And likewise also the men, leaving the natural use of the woman, burned in their lust one toward another; men with men working that which is unseemly, and receiving in themselves that recompence of their error which was meet. (Romans 1:26-27, KJV)
This passage begins “For this cause”: it depends on what went before, so you can’t read it out of context. Even so, some people believe that because this passage uses phrases like “against nature” it means that that same-sex relationships are paticularly bad, perhaps even being a transgression of natural law. But does the New Testament use what is “natural” as moral guidance anywhere else?
Leaving aside Romans for the moment, there are seven verses in the King James translation Bible where something is described as “natural” (φυσικός, phusikos, Strong’s 5446), “naturally” (φυσικῶς, phusikós, Strong’s 5447), or otherwise according to nature (φύσις, phusis, Strong’s 5449).
Just one of those verses – 1 Corinthians 11:14 – uses “nature” as a good thing that we should emulate (and even then that is debatable). Two of them – Galatians 2:15 and Galatians 4:8 – are neutral regarding nature as a moral authority. In three of them, “nature” is actually a bad thing.
Among whom also we all had our conversation in times past in the lusts of our flesh, fulfilling the desires of the flesh and of the mind; and were by nature the children of wrath, even as others. (Ephesians 2:3, KJV)
But these, as natural brute beasts, made to be taken and destroyed, speak evil of the things that they understand not; and shall utterly perish in their own corruption; (2 Peter 2:12, KJV)
But these speak evil of those things which they know not: but what they know naturally, as brute beasts, in those things they corrupt themselves. (Jude 10, KJV)
Unlike Romans 1:26-27, the seventh verse, 2 Peter 1:4 is about divine nature, which is obviously a good thing.
As well as the above verses, “nature” is used in the King James Version in eight other places, six of which are translations of different Greek words (1 Corinthians 2:14, 1 Corinthians 15:44, 1 Corinthians 15:46, Philippians 2:20, James 1:23, and James 3:6) and two of which are interpolations by the translators to add clarity (2 Timothy 3:3, and Hebrews 2:16). None of those verses suggest that “natural” behaviour is something that Christians should aim for.
Returning to Romans, in Romans 11:21-24 Paul describes God himself acting in a way that is contrary to nature:
For if God spared not the natural branches, take heed lest he also spare not thee. Behold therefore the goodness and severity of God: on them which fell, severity; but toward thee, goodness, if thou continue in his goodness: otherwise thou also shalt be cut off. And they also, if they abide not still in unbelief, shall be grafted in: for God is able to graft them in again. For if thou wert cut out of the olive tree which is wild by nature, and wert grafted contrary to nature into a good olive tree: how much more shall these, which be the natural branches, be grafted into their own olive tree? (Romans 11:21-24, KJV)
“Nature” just isn’t used as a moral force in the New Testament. We can’t simply look at something being “natural” and conclude that it is good, and look at something being “against nature” and conclude that it is bad. Yes, in Romans 1, Paul uses negative language about same-sex relationships, but he also uses negative language about opposite-sex relationships. There is simply no justification for the assumption that the negative language used about one is worse than the negative language used about the other.
Faith and Pride 
I have to say I disagree.
From my understanding, Paul comes to think negatively of the Same Sex relations he sees for two reasons.
1) His culture. He, like most Jews, would have understood the laws of Deuteronomy and Leviticus to outlaw same sex intercourse as a a crime punishable by death. As a Christian, he would have understood that Christ completed the law but of course, would have considered it sin.
2) Greek Religion. The Greeks used sex as an expression of love for their gods. When Paul encountered Greek temples, he saw how they used sex to celebrate their faith and would have come to identify the common occurnace of same sex relations with the worship of these pagan gods.
From what I read and understand, Paul did indeed consider that people who had sex with a member of the same gender had deviated from the reason they were created “by leaving their natural use”. Paul, in my opinion, clearly meant that same sex relations were unatural and an affront to God. I don’t beleive there can be any misunderstanding that when he said “unnatural” he meat exactly that.
This is a case of Paul being wrong. Simple as that in my opinion. Blinded by the culture in which he grew up and it’s opposition to anything Gentile and the points expressed above, he honestly believed same sex relations to be a pretty serious sin.
As we know those who wrote the scripture, while guided by God, were but men and their situation, culture and understandings sometimes disfigured the message brought by Christ to all man kind – A God that loves love and never condemns it.