Can you marry your half-niece? (The prohibition of incest)

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In this blog post, we answer the following question: Can you marry your half-niece? We also talk about avunculate marriage, what does a family mean and what is the prohibition of incest. 

Can you marry your half-niece?

Technically, you can marry your half-nice. Marriages between uncles and nieces or aunts and nephews are forbidden in most of the countries. However, the law does not prohibit marriages between half-relatives. The marriage between an uncle and his niece is known as an Avunculate marriage. 

What is Avunculate Marriage? Can uncles and nieces get married?

First of all, it is important to emphasize that this is a very controversial topic! Another thing, uncles and nieces are third-degree collateral relatives.

Avuncular marriage is the name given to the marriage between uncles and nieces, that is, between collateral relatives in the third degree. Thus, is avuncular marriage permitted by the national legal system?

It turns out that the Civil Code of 1916 prohibited such a marriage. However, in 1941, the law was sanctioned, which allowed it as long as the spouses had the proper judicial authorization and submitted to a prior medical examination. 

It dealt with the issue only from a medical perspective, so it did not discuss moral or religious issues, but only issues related to the health of the new couple and their future children.

The spouses should have the judicial authorization and the certificate of two doctors with recognized capacity, exempt from suspension, to examine them and certify their sanity, stating that there is no inconvenience, from sanity, under the point of view of the health of any one of them and the offspring, in the realization of the marriage, certifying that their children would not be born with health problems or deformities.

In 2002, avuncular marriage was again prohibited, providing that “the brothers, unilateral or bilateral, and other collaterals, up to the third degree (uncles and nephews), cannot marry each other“.

However, it is currently possible to recognize the marriage between uncles and nieces as long as it does not pose risks to the life and health of the new couple, their eventual children and has judicial authorization.

OBS: In the judicial process to qualify for an avuncular marriage if the two doctors appointed by the judge disagree as to the suitability of the marriage, the newlyweds may jointly request the appointment of a third doctor, as a tiebreaker.

Whenever, at the judge’s discretion, it is not possible to appoint two suitable doctors, he may instruct only one doctor to carry out the examination, whose opinion will be conclusive.

When the betrothed do not comply with the medical report, they may request a new examination, in which the judge will determine its realization if it recognizes the merits of the allegations or if the betrothed are attached to the divergent certificate signed by another doctor.

The medical examination will be done extrajudicially, without any formality, upon simple presentation of the request issued by the judge.

What is a family?

Much has been debated and is still being debated, the problem of the universality of the family institution. Claude Lévi-Strauss reaches important conclusions, although it is not yet known to say apodictically what the family is or what future awaits him. 

It is proven that it is at the extremes of the cultural scale (if it can be said that way), in the simplest and most civilized towns, where the monogamous type of conjugal family prevails, now disregarding its specific forms. 

While it is in non-archaic towns and with a super elaborated social development in which there are types of an organization where the conjugal family practically disappears. 

Thus in the case of the Nayar, on the Malabar coast of India: the marriage ceremony, purely symbolic, did not create a permanent union, since men engaged in war, and married women were authorized to admit lovers at pleasure, whereas the children belonged only to the maternal line, regardless of who the father was (cf. Lévi-Strauss 1956: 10).

As it happens, above the conjugal level, the functional value of the family grows socially (domestic family); below the conjugal level, the functional value of the family tends to disappear; and right at the conjugal level, the functional value of the family stabilizes, whatever the specific functionality and the system by which the couple is assigned or chosen.

The “family” designates a social group originated by marriage, nuclearly composed of husband, wife and children (although other relatives may be added), and bound by legal ties, by economic and social norms, by sexual rules and by special personal feelings.

Marriage, as a condition of the family, appears both monogamous and polygamous (and this, as polygyny or polyandry), so it can be said that monogamy is not inscribed in human nature. It is a cultural question as it can be, in some society, the repulsion towards singleness or childless couples.

Family ties are very diverse. Of course, they are not reduced to the satisfaction of the sexual impulse, to which most of the towns provide not a few opportunities. 

The prohibition of incest 

If the natural order is characterized by the “universal” law and the cultural order, by the particular “rule” (which excludes naturally possible solutions), here in the prohibition or taboo of incest we discover the articulation between both orders: it is of a universal rule. 

The prohibition of incest presents, without the slightest misunderstanding and inseparably gathered the two characters in which we recognize the contradictory attributes of two exclusive orders: it constitutes a rule, but the only social rule that has, at the same time, a character of universality “(Lévi-Strauss 1949: 42). 

It is anchored in the pre-cultural, represents just the point of immersion of culture and, as Lévi-Strauss wants to demonstrate, constitutes a culture itself. In the end, he believes it corroborated: “If the interpretation we proposed is exact, the rules of kinship and marriage are not made necessary by the state of society. They are the state of society itself” (Lévi-Strauss 1949: 568). 

1. The prohibition would be due to a social reflection on a natural phenomenon: the tares resulting from blood unions (L. H. Morgan; H. Maine). It is not admissible, given that this difficulty would have been avoided, if the prohibition did not exist, as in other animal species; Furthermore, primitive societies were completely unaware of genetics.

2. The ban would be the effect of a natural physiological horror of incest (E. Westermarck; H. Ellis). But, on the contrary, psychoanalysis reveals the existence of the desire for incest. Furthermore, how do you relate to the same degree of consanguinity, some are considered incest and others are not?

3. The prohibition would be originated purely by a social rule, fixed for different reasons according to the groups, whose biological incidents would be accidental and secondary (J. F. McLennan; J. Lubbock; E. Durkheim). But this does not satisfy either. The problem of the incest taboo is not explained by the different historical configurations that have arisen in such and such societies.

Nothing would prevent a man, biologically speaking, from marrying his mother, his sister or his daughter. But from the moment the biological family does not live alone and has to seek an alliance with others to perpetuate itself, and since the need for society to exist, the incest prohibition arises, which is then broken down into multiple rules that outlaw or prescribe certain types of spouses. 

In other words: “from the moment I forbid the use of a woman, who thus becomes available to another man, there is, somewhere, another man who renounces a woman who by this fact makes herself available to me.”(Lévi-Strauss 1949: 89-90). 

This universal and foundational rule of society embodies the quintessential donation rule, which requires giving the mother, sister or daughter to another person. He is radically opposed to the antisocial way of achieving things for himself and for himself instead of obtaining them from another and for another, a procedure that is typically incestuous. 

So “incest is socially absurd before being morally guilty” (Lévi-Strauss 1949: 562). In a phrase, the prohibition of incest implies the condition that makes possible the existence of any kinship system and, in reality, the existence and persistence of all human society.

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In this blog post, we answered the following question: Can you marry your half-niece? We also talked about avunculate marriage, what does a family mean and what is the prohibition of incest. 

Technically, you can marry your half-nice. Marriages between uncles and nieces or aunts and nephews are forbidden in most of the countries. However, the law does not prohibit marriages between half-relatives. This type of marriage is also known as an Avunculate marriage. 

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FAQ on Can you marry your half-niece?

Can you marry your niece?

Marriages between uncles and nieces or aunts and nephews are forbidden in most of the countries. However, the law does not prohibit marriages between half-relatives. 

How much DNA do I share with my half-niece?

You share about 12.5% DNA with your half-niece. But of course, this may vary depending on the family ties. 

What is a half-niece?

A half-niece is the child of your half-sibling (with whom you share your father or your mother). You share about 12.5% DNA with your half-niece. 

What does incest mean?

Incest means having a sexual relationship with a family member or a close relative. Incest can happen between people in consanguinity (blood relations), and sometimes those related by affinity (marriage or stepfamily), adoption, clan, or lineage.

Can an uncle and niece have a baby?

An uncle and a niece can have a baby, however this would be morally and legally wrong. Moreover, they should be aware that there is a high risk of having a child with an autosomal recessive condition. 

Can I marry my sister’s daughter?

You cannot marry your sister’s daughter since this type of marriage (avunculate marriage) is prohibited in almost all countries. Your relationship is considered incest, which is also punished by law. 


DeYoung, M., & Lowry, J. A. (1992). Traumatic bonding: Clinical implications in incest. Child Welfare: Journal of Policy, Practice, and Program, 71(2), 165–175.

Pendergrast, M. (1995). Victims of memory: Incest accusations and shattered lives. 

“Incest”. Author: Julia Máxima Uriarte. To: Last edition: March 10, 2020.

Coontz, Stephanie

  2005 History of marriage. How love conquered the world. 2006.

Cuisenier, Jean

  1974 “Structuralism”, in Philosophy

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