There is a misconception currently held by some Christians that Paul coined the word ἀρσενοκοῖται from Lev. 20:13 as found in the Greek Septuagint (LXX), which is the oldest translation of the Hebrew Bible.:
Και ος αν κοιμηθη μετα αρσενος κοιτην γυναικος βδελυγμα εποιησαν αμφοτεροι θανατουσθωσαν ενοχοι εισιν·
The idea is based upon the existence of the words αρσενος κοιτην in that verse, but this is flawed scholarship. Since αρσενος means male, and κοιτην means bed, ANY Greek sentence that mentions a male and a bed will have forms of those two words in it. Leviticus 18:22 and 20:13 are not the only verses in the Septuagint containing those words, as seen below.
και νυν αποκτεινατε παν αρσενικον εν παση τη απαρτια και πασαν γυναικα ητις εγνωκεν κοιτην αρσενος ζωγρησατε αυτας
πασαν την απαρτιαν των γυναικων ητις ουκ οιδεν κοιτην αρσενος ζωγρησατε αυταςAnd now kill every male among all children. But every woman who has not known the bed of a male, take them alive. All the women children who have not gone to the bed of a male, take them alive.
και ουτος ο λογος ον ποιησετε παν αρσενικον και πασαν γυναικα γινωσκουσαν κοιτην αρσενος αναθεματιετε
και ευρον απο των κατοικουντων ιαβις γαλααδ τετρακοσιας νεανιδας παρθενους αι ουκ εγνωσαν ανδρα εις κοιτην αρσενος και ηγον αυτας εις την παρεμβολης εις σηλω η εστιν εν γη χανααν
And this is the word that you will do: every male, and every woman who has known the bed of a male, you will destroy. And they found among the inhabitants of Jabesh Gilead four hundred young virgins who had not known a man in the bed of a male, and the brought them into the camp into Shiloh which is in the land of Canaan.
In each of these four verses, the phrase “bed of a male” is in relation to women who have not known that location, that is, women who were virgins.
In Leviticus, however, we have a different set up. Lev. 20:13 includes the phrase μετα αρσενος κοιτην γυναικος.
In this verse, αρσενος (a male) is preceded by μετα (with), while κοιτην (a bed) is paired with the genitive γυναικος (of a woman). This agrees exactly with the Hebrew text, that is, with a male (in) a woman's bed.
Ἀρσενοκοῖται, on the other hand, is NOT derived from the word for bed, but from the verb meaning “lie down.” This verb, κειμαι, in some of its forms, uses the construction κοιτ-. Therefore ἀρσενοκοῖται does not mean male beds, but rather, those who lie with males.