There is a great ethical difference between same-gender and opposite-gender sexual relations, whether they be in a committed marriage, living common-law, or a one-night stand. The difference is reflected in the moral commandments of the Bible and Christianity before the mass apostasy of AD 249-251, which would imply vastly different standards as to what is permitted.
The Scripture and its first interpreters in church history frequently and uniformly condemn heterosexual lust, rape, or other unmarried relations, but almost nothing in the homosexual sphere.
For instance, Jesus spoke against a man lusting after another woman, but not after another man (Matthew 5:28). Indeed, Christ said nothing at all against same-sex-loving people or what we today call homosexuality. Most of the biblical mentions of lust are in the prophecies of Ezekiel, always in an opposite-gender context.
Opposite-sex relations are frequently mentioned in the New Testament, but only a few about homosexual ones. Prostitution is usually — but not always — between different genders in both the Bible and contemporary society. Contrary to some misinterpretations, Romans 1:27 does not say homosexuality is a sin, but a punishment for prior misdeeds.
The reason for milder biblical treatment is easy to see. Heterosexual relations can result in a new life, a new human being, coming into existence, even though the man and woman try to prevent conception. This often leads to abortion, which was roundly condemned by the church fathers who were the first interpreters of the Bible and put into writing the oral teachings and practices of Jesus and the apostles.
No abortion or an unwanted pregnancy has ever resulted from same-gender sex. A gay man and a lesbian may participate in all the love and gratification each wants to their individual heart’s content but not with each other; there is no danger to a third person. Of course, there is the chance of spreading disease, but this applies to heterosexual relations as well.
Four comprehensive collections of Christian ethics and life were produced before AD 230, none of which forbids homosexual behavior but is firmly against heterosexual misbehavior.  One of them forbids fellatio of a woman on a man,  but not by a man on a man, probably because the circumstances of nudity and passion could easily lead to the real thing, with the prospect of an unwanted child.
A few early churchmen disapproved of “men abusing themselves with men” or “men defiling each other.” This phraseology would tend to indicate that God does not condemn homosexual acts in themselves but only ones that are abusive and defiling due to other factors. After all, opposite-gender relations may or may not be abusive or defiling, even between spouses.
The key here is the prohibition of a male “lying with a man as with a woman” (Leviticus 18:22) rather than all homoerotic interactions. In the world surrounding the Bible and early church, women occupied a social and familial position subordinate to men, little different from slaves or animals. Treating a man like a woman in bed may have been forbidden only because it meant subjecting him to an inferior status, and thus abusing and defiling him by the standards of that culture, which would not apply in the present-day culture valueing gender equality. This would be among the “other factors” that gays and lesbians in our culture must avoid to remain on the Christian path.
Even if we choose to assume that all same-gender intercourse is a sin, the number of references to it in the early literature are overwhelmed by disapprovals of unmarried heterosexual relations. Comparing it to a word-count of other prohibitions in the Bible and other early Christian sources, same-gender sexual relations are more serious than buying a lottery ticket or missing a church service, but less blameworthy than overeating or gossiping, even about somebody else’s sex life.
In short, original Christianity routinely condemned opposite-gender intercourse for good reason but said little clear against same-gender relations within the same circumstances. This makes one wonder if homosexual relations were and are not as big a deal for the church as the institutional church power brokers say they are.
 Didache 2 (circa AD 70-150); Letter of Barnabas 19 (circa AD 100); Revelation of Peter 25 (before AD 150); Athenagoras A Plea for the Christians 35 (circa AD 177); Minucius Felix The Octavius 30 (circa AD 166-210); Tertullian On the Soul 37 (AD 202) and Exhortation to Chastity 12 (AD 204); and Hippolytus Philosphumena 9.7 (early 3rd century AD).
 Letter of Barnabas, Didache, Didascalia, and Sentences of Sextus.
 Letter of Barnabas 10.8.
 David W T Brattston, Traditional Christian Ethics (Bloomington, Indiana: WestBow Press, a division of Thomas Nelson and Zondervan, 2014) vol. 4.
A retired attorney whose articles on early and contemporary Christianity have been published by a wide variety of denominations in every major English-speaking country, Dr. David W. T. Brattston holds degrees from three universities and is currently studying for a master of arts in theology from Acadia Divinity College in Nova Scotia, Canada.