Certainly, one of the laws commanded to the B'nai Noach is to marry and have children. In Genesis 2:24, man is commanded thus: "Therefore a man shall leave his father and his mother and shall cling to his wife and they shall be one flesh." It is furthermore stated, Genesis 9:1 "So G-d blessed Noah and his sons, and said to them: 'Be fruitful and multiply, and fill the earth'." These laws very specifically forbid the acts of celibacy and solitude as ways of approaching G-d. One is in fact commanded to be a functional part of society, wedding and bearing children. In fact, the passage quoted above, "...and they shall become one flesh" is often interpreted to bear a child. This is the only way that a man and woman can truly be said to have become one flesh. This law is to prevent those who would rather move off to some cave in a mountain in an attempt to get close to G-d, and 'become so heavenly minded that they become no earthly good'.
    Hence, it is obvious that sexuality, in and of itself, is not forbidden, but in fact required of all mankind, provided it is experienced in the appropriate manner. However, there are cases in which sexuality is not appropriate, and are all enumerated in the Bible in Leviticus Chapter 18.

Noachites are forbidden to have sexual intercourse with the following persons:

1) Mother
2) Father
3) Daughter
4) Son
5) Father's or Mother's Sister (i.e. Aunt)
6) A man with a woman in an unnatural way (Sodomy)
7) Another man's Wife
8) A male with another male
9) A male or female with an animal

    Therefore, Incest, Male Homosexuality, Adultery, Sodomy, and Beastiality are all strictly forbidden. It is interesting to note that female homosexuality, though frowned upon and against the spirit of the Seven Universal Laws, is not specifically forbidden. However, of all of the forbidden illicit relationships described above, only male homosexuality is described by the Scriptures as "an abomination to G-d". Even beastiality is not so described. This is due to the fact that male homosexuality is so devastating spiritually. For a man is considered the living representation of the Active Principle, and in mixing two active principles you arrive at a condition tantamount to a spiritual train wreck. Even nature bears out this fact in every faucet of existence. It is a fact that opposite polarities attract, and like polarities repel. No homosexual was ever born to a homosexual relationship, nor was anything else.
    Every society in history who ever condoned homosexuality was short-lived and broken at the very height of its power. For instance, remember the ancient Greek empire, which was overthrown by a tiny Jewish upsurge led by the Maccabees.
    And one can hardly ignore the destruction to the body so evident in this devient behavior, such as the excessive, abnormal weakness and the horrible diseases that we are only just beginning to discover.
     It is also forbidden under the Seven Laws to castrate any male, whether man or beast. This falls under the catagories of the Cruelty to Animals as well as Forbidden Sexual Relations.

Noachites are permitted to have sexual relations with the following individuals after the death of the relative in question:

1) Father's Wife (not one's mother)
2) Brother's Wife
3) Wife's Sister
4) Daughter-in-law
5) Stepdaughter