Do Not Have Forbidden Sexual Relations.

Human beings are not sexual objects, nor is pleasure the ultimate goal of life.

Five of the six types of relations which are forbidden by G-d to Gentiles are covered in Gen. 2:24: "Therefore a man shall leave his father and his mother and cling to his wife and they shall become one flesh."

This verse explicitely forbids relations with one's mother, one's father's wife, a wife of another man, another male, and an animal. A Gentile is also forbidden to have relations with his maternal sister, which is learned from Gen. 20:13: "Moreover, she is indeed my sister, my father's daughter, though not my mother's daughter; and she became my wife."

(Note that Abraham said this to appease Abimelech. It was actually only figuratively true in his case, since Sarah was the daughter of Abraham's brother. So they had the same paternal grandfather, who people often referred to as "father".) It also was universally accepted that father-daughter relations would be included, as evidenced by the disgrace of Lot after he had relations with his two daughters, following G-d's destruction of Sodom and Gomorrah (Gen. 19:29-36, and Rashi's explanation of Gen. 20:1).

Relations of a female with a female are likewise an abomination to G-d which is included as one of the subjects of the verse Lev. 18:3, which speaks against the immoral practices of the ancient Egyptians and Canaanites, and which Lev. 18:30 refers to as "abominable traditions." About these the Midrash (Sifra) specifies: "A man would marry a man, a woman would marry a woman, and a woman would be married to two men."  Also see Gen. 6:1-4,  Gen. 20:3, & Gen. 19:5-7.

Forbidden Sexual Relations encompass the following:

 

1. against (a man) having union with his mother;
2. against (a man) having union with his sister;
3. against (a man) having union with the wife of his father;
4. against (a man) having union with another man's wife;
5. against (a man) copulating with a beast;
6. against a woman copulating with a beast;
7. against (a man) lying carnally with a male;
8. against (a man) lying carnally with his father;
9. against (a man) lying carnally with his father's brother; and
10. against engaging in erotic conduct that may lead to a prohibited union.