Gender, in that usage.
The term gender itself has exists for centuries as a synonym of sex
Trannies and Zig Forums
Joshua Thomas
Andrew Parker
It isn't "men who lie with mankind" it is "abusers of themselves with mankind", not the same thing
Ayden Hall
The Lord doesn't make mistakes and all is done according to his will. Sin has corrupted the world and with every passing generation the human genome becomes more corrupted. People having these 'transexual' feelings/emotions experience a different symptom of our corrupt human nature than others. However, it is not sinful to suffer transexual temptation; It is only sinful to act upon it:
◄ Deuteronomy 22:5 ►
A woman shall not wear man's clothing, nor shall a man put on a woman's clothing; for whoever does these things is an abomination to the LORD your God.
Tyler Jenkins
The Greek word used is arsenokoitai in both the LLX and Corinthians. The KJV's translation is of "arsenokoitai" as "abusers of themselves" is objectively wrong. Arsenkoitai means, literally, "manbedder" koitai is where we get the English words coitus and cot from. Arseno means man.
Paul was quoting the LLX and they are indeed, the same thing: homosexuals.