Forbidden relationships in Judaism (Hebrew: עריותArayot, or איסורי ביאה Isurey bi'ah) are those intimate relationships which are forbidden by prohibitions in the Torah and also by rabbinical injunctions. Engaging in some forbidden relationships is considered such a serious transgression in Jewish law that unlike most other negative commandments, in which one is allowed to transgress the commandment when a life is on the line, engaging in a forbidden relationship is forbidden, even when the alternative is death.[1]

Adultery and niddah

It is forbidden for a man to have sexual relations with a married woman not his wife, (Leviticus 18:20) (see adultery) and a man is not allowed to have sexual relations with any woman - including his wife - during her menstrual period (Leviticus 18:19), until after she undergoes the proper cleansing procedures in a mikveh.


Exogamous marriage is forbidden in Judaism. In relation to intermarriage with a Canaanite the prohibition is biblical,[2][3][4], while marriage with other nationalities is forbidden by the Talmudic sages.[5] Two special classes of people in Israelite society - Nethinim and Gibeonites - were regarded as foreigners in relation to this rule, and hence the Talmud forbids marriage to them.[6]

Incestuous relations

Sexual relation with certain close relations are forbidden. Though they are generally called incestuous relations, the biblical list does not necessarily correspond to those prohibited under state laws. The prohibited relations are:

Rabbinically prohibited relationships

In addition to the relationships biblically prohibited to Jews, rabbis have gone further to prohibit certain additional relationships with various blood relatives and in-laws. These are called "Shni'ot" (secondary prohibitions). Some of these are:[1]

Exclusions from the assembly

The Bible prohibits men from taking part in the qahal of Hashem if they are members of certain categories of people. Jewish tradition considers this to be solely a limitation on marriage.


Jewish people are prohibited from marrying with the following groups:

As the people currently living in those areas may not be be descended from the original peoples, these three prohibitions do not apply today.[7]


The Talmud forbids marriage to a mamzer.[8] This includes children resulting from an incestuous marriage, and children resulting from adultery,[9] but does not include the children of two unmarried people, who are not related to each other.[9] A convert may marry a mamzer, but the children are still mamzerim.[10]


Jewish tradition also forbids marriage to a man who has been forcibly emasculated; the Greek term spadones, which is used to refer to such people, is used in the Septuagint to denote certain foreign political officials (resembling the meaning of eunuch).[9] The Jewish prohibition does not include men who were born without visible testicles (conditions including cryptorchidism), or without a visible penis (conditions including hermaphroditism).[9] There is dispute, even in traditional Judaism, about whether this prohibited group of men should include those who have become, at some point since their birth, emasculated as the result of a disease.[11]

Special rules for priests

Israelite priests (kohanim) are not allowed to marry:

Some of these prohibitions are biblical, and some are rabbinical.

The Kohen Gadol (high priest) must also not marry a widow (Lev. 21:14). Sexual relations with a widow outside of marriage are also forbidden (Lev. 21:15). He is required to marry a virgin maiden (Lev. 21:13). However, if he was married to a woman otherwise permitted to a kohen and was then elevated to the high priesthood, he may remain married to her.



Orthodox Judaism interprets (Leviticus 18:22) as forbidding men from lying with other men in the manner in which they would with a woman. (Leviticus 18:14)specifically prohibits such relationships with one's father or uncle.[16]

There are three reasons rabbis give for homosexuality being prohibited in Jewish law:[17]

  1. It is a defiance of gender anatomy, which is unlike God's intention of procreation and sexual activity
  2. The sexual arousal involved results in a vain emission of semen
  3. It may lead a man to abandon his family

There is no explicit prohibition in the Torah against lesbianism; however Jewish law prohibits it, under the category of "the activities of (ancient) Egypt (see Lev. 18:3)".[18] However, it is not considered adultery, and does not prohibit the woman to a kohen.[19]


Reform Judaism interprets Leviticus 18:22 as forbidding men from using sex as a form of ownership over men. Reform Jewish authors have revisited the Leviticus text and ask why the text mentions that one should not lie with a man “as with a woman.” If it is to be assumed that the Torah does not waste words, the authors ask why the Torah includes this extra clause. Most Reform Jews suggest that since intercourse involved possession (one of the ways in which a man ‘acquired’ a wife was to have intercourse with her), similar to the Christian theology of using sex to 'consummate' a marriage, it was abhorrent that a man might acquire another man – it is not the act of homosexual intercourse itself which is abhorrent, but using this act to acquire another man and therefore confuse the gender boundary. [20]


Men and women are forbidden from engaging in bestiality. (Leviticus 18:23) It is considered an abomination according to the Torah.[1]


Rather than being seen as merely a literary device to quickly describe the populating of the earth, the biblical instruction to go forth and multiply[21] was interpreted by the classical rabbis to mean that it was the duty of every male Jew to marry as soon as possible[22]. Several Talmudic rabbis urged that children should be married as soon as they had reached the average age of puberty, which was deemed to occur at 14 years of age[23]; however, it was also strictly forbidden, by classical rabbinical literature, for parents to allow their children to marry before the children had reached this age[23]. Despite the young threshold for marriage, marriages with a large age gap between the spouses (eg. between a young man and an old woman) were thoroughly opposed by the classical rabbis[24][25]

The classical rabbis saw 18 as the ideal age to become married[26], and anyone unmarried after the age of twenty was said to have been cursed by God[27]; rabbinical courts frequently tried to compel an individual to marry, if they had passed the age of twenty without marriage[9]. Nevertheless, the classical rabbis viewed study of the Torah as a valid reason for remaining unmarried, although they were only rarely willing to regard life-long celibacy favourably[28]. Since the classical rabbis viewed marriage as a duty deriving from the instruction to go forth and multiply[22], they also believed that the duty to marry ended once the husband had fathered both a son and a daughter[29]; despite this, they also argued that no man should live without a wife even after he has several children[29].

Ability to give consent

Children, however, were not regarded as old enough to make an informed decision, and so could not consent to marriage themselves[9], although marriage to a female child was still permissable if her father consented, whether she agreed to it or not[9]; if the father was dead, such consent could be given by her mother, or her brothers, but in this latter case the girl could annul the marriage when she reached the "standard" age of puberty (12), if she wished[9].

The mentally handicapped, and deaf-mutes, were also regarded, by traditional Jewish law, as being unable to give their consent; indeed, marriage to such people was forbidden. However, the rabbis allowed deaf-mutes to marry each other.[9]


  1. 1.0 1.1 1.2 Eisenberg 2005, p. 324.
  2. Genesis 24:2-4
  3. Genesis
  4. Deuteronomy 7:3
  5. Kiddushin 68b
  6. Yadayim 4:4
  7. Rabbi Joseph Karo, Shulchan Aruch, III:4:10 and commentaries, Habahir edition, Leshem publishers
  8. Yebamot, 4:13
  9. 9.0 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 9.9 Jewish Encyclopedia, Marriage Laws
  10. Maimonidies, Mishneh Torah, Sanctity, Laws of Sexual Prohibitions, 15:7-8
  11. Jacob ben Asher, Eben ha-'Ezer, 5
  12. Leviticus 21:17 (in the King James Version, it is verse 14 instead)
  13. Ketubot 22a
  14. Ketubot 27a
  15. Yebamot 24a
  16. Eisenberg 2005, p. 327.
  17. Eisenberg 2005, p. 325
  18. Rabbi Joseph Karo, Shulchan Aruch, III:20:2
  19. Beit Sh'muel, ad. loc. based on Maimonidies
  21. Genesis 1:28
  22. 22.0 22.1 Maimonides, Minyan haMitzvot, 212
  23. 23.0 23.1 Sanhedrin 76b
  24. Yebamot 44a
  25. Sanhedrin 76a
  26. Pirkei Abot 5:24
  27. Kiddushin 29b
  28. Yebamot 63b
  29. 29.0 29.1 Yebamot 61a

Further reading

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