This week's Torah portion outlines most of the Torah's rules regarding whom one may and may not marry.1 This article will explore this area of Jewish law.

Forbidden Blood Relatives

A man or woman may not marry any of his or her close relatives.2 These forbidden combinations include:

  1. A parent and a child
  2. A grandparent and a grandchild
  3. Siblings or half siblings
  4. An aunt and her nephew

Forbidden Relatives Through Marriage

  1. A man may not marry his mother-in-law or grandmother-in-law even after he divorces his wife or his wife dies.
  2. A man may not marry his wife's daughter or granddaughter even after he divorces his wife or his wife dies.
  3. A man may not marry his uncle's wife even after his uncle's divorce or death.

Forbidden Relatives Through Marriage Who Can Become Permissible

  1. A man may not marry his wife's sister even if he divorced his wife. If, however, his wife (or ex-wife) dies, he may marry her sister.
  2. In general, a man may not marry his brother's wife even if his brother divorces her or dies.
    If however, his brother died without children, by Torah law, he (or another surviving brother) should marry her in order to "establish a name" (i.e., have children) for the deceased brother. This practice is called yibum. The Ashkenazi custom is to avoid yibum3 by conducting a ceremony called chalitzah. After this ceremony, the wife is permitted to marry whomever she wishes except for her deceased husband's brothers or a kohen (priest; see below). In Sephardic communities, the mitzvah of yibum is still practiced (for more, see Yibum and Chalitzah).

In the case of close relatives that are forbidden to marry by Torah law, if they do "marry" each other, the marriage is not considered valid. If they are only forbidden by rabbinic law,4 the marriage, although prohibited, is valid.

Individuals Who May Not Marry Within the Jewish People


A man or a woman who is the child of a forbidden union is considered a mamzer (mamzeret for a female).5

If the mother is Jewish and the father is not, the child is not considered a mamzerA forbidden union is defined for this purpose as one in which the man and woman were forbidden to marry each other. This could be either because the woman was married to someone else at the time of the union, or because they are close relatives (see above).

(Contrary to popular belief, if the parents were permitted to marry each other, but were not actually married, a child from their union is not a mamzer.)

If the mother is Jewish and the father is not, the child is not considered a mamzer.6 A girl born of such a union, however, may not marry a kohen (see below).

Petzu'ah Dakah

A man whose genitalia were crushed or otherwise maimed may not marry within the Jewish people. The details of this law are beyond the scope of this article, but one who has a question in this regard should discuss it with a competent rabbi.7


It is forbidden for a Jew to marry a non-Jew. This sin is punishable by karet.8 In addition, the Talmud says9 that a man who commits this sin loses the spiritual protection of the brit milah—the circumcision, the covenant of Abraham.

Even if a Jew and a non-Jew have a wedding ceremony, the marriage is deemed invalid under Jewish Law.10 In the case when a child is born, he or she will not be considered Jewish if the mother is a non-Jew.11

Marriage Laws for a Kohen

A kohen (priest, a male descendant of Aaron) has additional restrictions and guidelines regarding whom he may marry.12

A kohen may not marry:

  1. A woman who was divorced. This would apply even to the kohen's own ex-wife.
  2. A woman who had a chalitzah ceremony (see above)
  3. A convert. This is true even if the woman was converted as a small child.
  4. The daughter born to a kohen of a relationship forbidden to a kohen—known as a chalalah.13
  5. The daughter of a Jewish mother and a non-Jewish father.14
  6. A woman who had sexual relations with a man whom she is forbidden to marry, such as a close relative (see above), a mamzer, or a non-Jew.
  7. The widow of a disqualified kohen (see below).15

As long as they remain married, however, the kohen does not receive any privileges of a kohenIf a kohen does marry any of the above women, despite the fact that the marriage is forbidden, it is valid. For as long as they remain married, however, the kohen does not receive any privileges of a kohen. For example, he does not get called to the Torah first, nor may he administer the Priestly Blessing.16 The priesthood itself, however, remains with him and can never be renounced.17 For this reason, the prohibitions that apply to a kohen (that he may not enter a cemetery, etc.) still apply to him.

A male child of such a marriage is considered a disqualified kohen—a chalal. He does not have any of the privileges or prohibitions18 of a kohen. (In the case when a kohen married a woman whose father was not Jewish, the status of the child born to this marriage is unclear.19)

The Daughter of a Kohen

It is considered an inappropriate match for the daughter of a kohen to marry a non-kohen who is not versed in Torah. Rather, she should marry someone who is fluent in at least one tractate of the Talmud. If he does not know even one tractate, it is proper for him to study one before the wedding.20

Second Marriages

  • If a pregnant woman gets divorced or is widowed, G‑d forbid, she may not re-marry while pregnant. In addition, after having a baby, a woman must wait twenty-four months before she may remarry.21 This law ensures that she will be able to nurse and nurture the baby properly—without the possibly conflicting attention demanded by a new husband who may not have the child's best interests at heart.
  • When marrying a man or woman who was divorced, one should ascertain that the previous marriage was terminated with a valid get (Jewish divorce). If a proper get has not been given, the (original) couple remains married according to Jewish law, despite any civil divorce or prolonged separation. In a case when a woman was married and did not receive a get, and then marries another man (G‑d forbid), any child born from that union is considered a mamzer (see above).
  • A man may not remarry his ex-wife if she was married to another man in the interim.22
  • A woman must wait 90 days after divorce or the death of her husband (G‑d forbid) before remarrying.23 (Similarly, a woman who converts to Judaism must wait 90 days before she may marry.24)
  • A woman who was married twice, and each of her husbands died of natural causes, may be forbidden to remarry.25 One should consult one's rabbi in this regard.