The term "homosexual" was invented fairly recently, in the 19th Century, and the notion of "sexuality" is completely modern. Some terms and taboos for sexual practices, however, are much older than that.
While the Scriptures declare homosexual relations to be an "abomination", precisely what sexual practices were considered sinful is never spelled out in any detail. The KJV puts it like this: "Thou shalt not lie with mankind as with womankind: it is abomination". Leviticus 18:22. I know no Hebrew, but I am given to understand that the original is quite vague, and could even be stretched to mean "you should not have sex with a man in the same bed where you have sex with a woman", or "don't have sex with men the same way you have sex with women", which in the context of ancient Israel, might imply: "don't dominate your boy friend the way you dominate your wife and slaves". Moreover, I'm not sure an "abomination" (ritual impurity) is the same as a "sin".
The New Testament isn't much better on details. Nowhere is the conservative "Christian" sexual code of conduct—no homosexual sex, no oral sex, no recreational sex—set forth in any detail in the Bible. Where did all that baggage come from?
The term "sodomy" is thought to have originated with Peter Damian (1007-1071). Peter Damian, an Italian monk, in his life a Cardinal/Bishop and papal legate, more recently declared a "Doctor of the Church" by Pope Leo XII (and therefore a saint sans formal canonization) was an extreme ascetic. As abbot, he introduced an afternoon siesta, not because he was a slacker, but because he would stay up all night praying. Depictions of him as a patron saint usually have him holding a "discipline" (a whip) because he wrote a treatise praising self-flagellation as a means of mortification and penance. He was also the author of an estimated 180 other works. Typical of the philosophy of Damian was De divina omnipotentia which, among other things, inquired whether God could undo what has been done, for example, restore a woman's virginity. (Damian's answer was: "Yes", in a bold defense of the omnipotence of God which did not flinch at the rejection of the logical principle of noncontradiction.)
Among St. Peter Damian's most famous writings is Letter 31, the "Book of Gomorrah" (Liber Gomorrhianus), for which he invented the term "sodomy" and specifically condemned clerical pederasty and homosexual practices. For Jesus, the sins of the people of Sodom and Gomorrah were their lack of hospitality.
See Matthew 10: 5-15. (For the Sodom story,
see Genesis 19:5; for the Prophets' gloss on the story
see Ezekiel 16:49.) Damian, following fellow ascetic Paul (
Romans 1:24
et seq.) redefines "sodomy" as sexual practices which, by their "unnatural" character, reveal an underlying spiritual rebellion from God: self-love and idolatry.
Unlike Scripture, Damian left nothing to misinterpretation. He distinguishes between the various forms of sodomy beginning with solitary and mutual masturbation and ending with interfemoral (between the thighs) stimulation and anal coitus. From there, the term "sodomy" found its way into popular works by Albertus Magnus, Alan of Lille, and Thomas Aquinas, into canon law, and eventually the secular laws of nations.
Damian's precision has not always been emulated in subseqent centuries. In Anglo-American law, the first English statute criminalizing sodomy was passed during the English Reformation when powers of the ecclesiastical courts were transferred to the King's Courts. 25 Hen. VIII, ch. 6. From there, things tend to get murky again, as jurists revert to vagueness. Blackstone described "the infamous crime against nature" as an offense of "deeper malignity" than rape, a heinous act "the very mention of which is a disgrace to human nature," and "a crime not fit to be named." 4 W. Blackstone, Commentaries 215. It is sometimes impossible, reading early American statutes, to figure out precisely what sexual practices are prohibited. Blackstone notwithstanding, imprecision is not a virtue in writing laws. Does "buggery" include oral sex? How about "the abominable and detestable crime against nature"? What is "unnatural carnal copulation"? Is it the same as "unnatural carnal knowledge"? The United States Supreme Court exploited that vagueness in the case of Bowers v. Hardwick 478 U.S. 186 (1986) which upheld a Georgia prosecution of two gay men for oral sex. (As scholars have since pointed out, not all the statutes cited by Justice White as prohibiting "sodomy" in fact prohibited oral sex: some just banned anal sex).
Bowers v. Hardwick was recently overruled in the case of Lawrence v. Texas.