Fifty percent of marriages among Muslims are reportedly between first cousins, rising to 70% in Pakistan and Saudi Arabia. This preference for cousin marriage is inspired by the fact that Prophet Muhammad married his first cousin, Zaynab bint Jahsh (RA) in 627 CE. Earlier, the Prophet (ﷺ) had suggested to Zaynab that she marry his adopted son and former slave, Zayd bin Haritha (RA). While Zaynab was apparently unhappy with that marriage proposal initially because she was a Qurayshi and he, a freed former slave, she subsequently acquiesced to that marriage when the following verse was revealed shortly thereafter to the prophet:

It is not fitting for a believer, man or woman, when a matter has been decided by Allah and His Messenger, to have any option about their decision. [Sûrah Al-Aḥzâb, 33:36]

But, apparently, theirs was not a happy marriage according to Martin Lings’ 2006 book, Muhammad: His Life Based on the Earliest Sources (p. 213).

This, then, is how the Prophet reportedly ended up marrying her:

”One day, when the Prophet wanted to speak to Zayd about something and went to his house, Zaynab opened the door, and she stood in the doorway telling him that Zayd was out but inviting him [in] none the less. A look passed between the two cousins which made each one conscious of a deep and lasting bond of love between them. In a moment the Prophet knew that Zaynab loved him and that he loved her and that she knew he loved her. The Prophet refused her invitation, and as he turned to go, she heard him say, ‘Glory to God the Infinite! Glory to Him who disposeth men’s hearts!’ When Zayd returned she told him of the Prophet’s visit and of the glorification she heard him utter. Zayd immediately went to him and said: ‘I have been told thou camest unto my home. Why didst [thou] not enter, thou who art more dear to me than my father and my mother? Was it that Zainab hath found favor with thee? If it is so, I will leave her.’      ‘Keep thy wife and fear God,’ said the Prophet with some insistence.” (Lings, 212).

Then the following verse was revealed:

Behold! You did say to one who had received the grace of Allah and your favor: “Retain (in wedlock) your wife and fear Allah.” But you hid in your heart that which Allah was about to make manifest: you feared the people, but it is more fitting that you should fear Allah. Then when Zayd had dissolved (his marriage) with her, with the necessary (formality), We joined her in marriage to you: in order that (in future) there may be no difficulty to the Believers in (the matter of) marriage with (former) wives of their adopted sons once the latter have dissolved with the necessary (formality) (their marriage) with them. [Sûrah Al-Aḥzâb, 33:37)

Since all actions of the Prophet—referred to collectively as sunnah— serve as models that Muslims desire to emulate, the above incident leading to the Prophet marrying his cousin is now considered a sunnah and often actively pursued as a preferred marital match. This practice of cousin marriage supposedly credits the couple and their respective parents with some extra merit, pertaining to rewards in the Hereafter.

O Prophet! We have made lawful to you your wives to whom you have paid their dowers; and those whom your right hand possesses out of the prisoners of war whom Allah has assigned to you; and daughters of your [paternal] uncles and aunts, and daughters of your maternal uncles and aunts, who migrated (from Mecca) with you; and any believing woman who dedicates her soul to the Prophet, if the Prophet wishes to wed her. This is only for you and not for the believers (at large); We know what We have appointed for them as to their wives and the captives whom their right hands possess, in order that there should be no difficulty for you.  [Sûrah Al-Aḥzâb, 33:50]

So, marriages to all close relatives —including to “daughters of your uncles and aunts”— were permitted only to the prophet; these categories are what was not permitted to other Muslims.

Interestingly, and in spite of having this Divine permission to marry other closely related women, the Prophet subsequently married from various tribal lineages:  He did not marry such closely related ladies after marrying Zaynab. For example, he did not marry Umm Habib bint al-Abbas (RA) (Ibn Ishaq, Al-Tabari, Ibn Sa’d), although she was not only his cousin, but also the daughter of his foster brother. And he declined the marriage proposal from two women: Durrah bint Abi Salama(RA)   (aî Muslim 3413) and Umama bint Hamza (RA) (Ibn Sa’d: Bewley/Saad 8:115-116) [1]  because he discovered their fathers were his foster brothers.

Since giving as few as ten suckles to a baby by a wet nurse establishes a foster relationship between the wet nurse and the child (Al-Muwatta 30.12), foster relationships are relatively easy to acquire. Thus, based on verse 33:50 and backed up by verse 33:37, both cousin marriage and marrying children of foster parents are haram (forbidden) to the general Muslim population.

Accordingly, in the contemporary world, the question raised is this: What is so wrong with cousin marriage? Science provides us with a compelling reason: Cousin marriage increases chances of medical problems. With a higher amount of shared DNA, there is a higher risk of birth defects in babies born from such consanguineous marriages. Even in the absence of cousin marriages, the possibilities of genetic defects are higher in a population where there is a restricted social structure and thus a smaller genetic pool of eligible marriage prospects.

In Pakistan, where cousin marriage has been the norm for many generations, Prof. Anne-Marie Nybo Andersen (South Danish University), estimated that, compared to the five percent infant mortality prevailing in the general population,  infant mortality among “doubled cousin”  marriages (first cousin parents who were also children of first cousin parents) was  nearly three times higher (13 percent). And it was nine percent among first cousins once removed, and seven percent among second cousins. Also, among the double first cousin progeny, 41 percent of pre-reproductive age (pre-teen?) deaths were associated with the expression of detrimental recessive genes, with equivalent values of 26, 15, and eight percent for first cousins; first cousins once removed/double second cousins; and second cousins, respectively (

The most tragic report that I have read was an article by Izhar Ullah, Deformities in Charsadda: Cousin marriages, and the heavy price children pay, which appeared in the Karachi newspaper Dawn,(2015, October 15).  In a village populated by descendants of two families for the past 40 years, almost every third home had children suffering from birth defects. Disabilities included blindness, cerebral palsy, mental disorders, thalassemia (a group of genetic diseases that affect the body’s hemoglobin), physical deformities, as well as hearing and speech impairments.  And, while the residents were aware that offspring of inter-family marriages are likely to have birth defects or disabilities, they sadly continue with the practice due to “cultural norms.” This preferred practice, I suspect, goes back to a miscontrual of the lesson exemplified by the Prophet’s marriage with his first cousin, Zaynab.

A BBC report [2]   discussing Pakistanis in the United Kingdom found that 55% of marriages were between first cousins. And many children came from repeat generations of first-cousin marriages. The report stated that these children were 13 times more likely than the general population to produce children with genetic disorders.  They also found that one in ten children of first-cousin marriages in Birmingham in the U.K. either died in infancy or developed a serious disability.

The BBC report also stated that Pakistani-Britons, who account for only 3% of all births in the UK, produce about 30% of all British children with genetic illnesses. Studies show that the mean perinatal mortality in the Pakistani community of 16 per thousand significantly exceeded that in all other ethnic groups. Thus, congenital anomalies accounted for 41 percent of all British-Pakistani infant deaths.

Speaking against cousin marriage, the book Our Dialogue (Vol. 2, p. 308) 2  explains:

 “The Islamic view is that while marriage between cousins is permitted, it is certainly preferable to choose a marriage partner from outside one’s family. We have to distinguish between what is permitted and what is advocated.”

Thus, Our Dialogue reports that the Prophet once advised a companion to choose for his son a wife from another tribe; and for his second son, a wife from still another. I would argue, however, that cousin marriage was permitted by the Divine only as an exception to the prophet; it was never meant to be for all Muslims.

In conclusion, the above summary underscores the inherent potential danger arising out of consanguineous marriage —a relationship that should be highly discouraged, not only because of health issues but also in conformity with understanding the directives given by Allah in Sûrah Al- Aḥzâb, 33:50. At a minimum, a blood test should be made mandatory to weed out potential problems arising out of such marriages.

So then, educated with this knowledge, will the majority of Muslims take heed and modify their preference for marriage matches?

[1]    Ibn Sa’d: Kitâb Al-Tabaqat Al-Kabîr. Vol 8: The Women of Madina. Tr. Aisha Bewley. Ta Ha Publishers: London.

[2] “Our Dialogue”. apkar pk (undated, sixth edition). Available from Muhammad Arif, 404 Qamar House, M.A. Jinnah Road, Karach 74000, Pakistan. Phone: 001-92-21-231-2495. Fax: 001-92-21-231-0908

Saleem Ahmed, Ph.D.

Saleem Ahmed, Ph.D.

Born in India, raised in Pakistan; and has been living in Hawaii since 40+ years. Obtained an M.S. degree in geology from the University of Karachi in 1961 and a Ph.D. in Soil Science from the University of Hawaii in 1965. read more


  • Maryam Baksh

    Maryam Baksh

    September 6, 2020 - - 9:33 am

    Islam allows marriage of cousins…without doubt. There are numerous islamic issues with this article trying to argue the opposite:

    1. The Prophet صلى الله عليه وسلم married his own daughter Fatimah to her first cousin, Ali رضي الله عنه

    Would he do this if it was for Prophets only?

    2. In the Ayah directed at the believers stating who *not* to marry, cousins are not stated in any shape or form. Allah lists mom’s, grandma’s, nieces paternal and maternal, etc but not once a cousin.
    (Surah nisaa 4:23]

  • Saleem Ahmed

    September 7, 2020 - - 11:59 pm

    Let us first review some history:
    1. The Battle of the Trench occurred in February 627 CE
    2. The prophet married Zainab the following month
    Now, let us consider this Qur’anic verse:
    33.50. O Prophet! We have made lawful to thee your wives to whom you have paid their dowers; and those whom your right hand out of the prisoners of war whom God has assigned to you; and daughters of your paternal uncles and aunts, and daughters of your maternal uncles and aunts, who migrated (from Mecca) with you; and any believing woman who dedicates her soul to the prophet if the prophet wishes to wed her. This is only for you, and not for the believers (at large). We know what We have appointed for them as to their wives and the captives whom their right hands Possess; in order that there should be no difficulty for you. And God is Oft-Forgiving, Most Merciful (Surah Al-Ahzab).
    This made lawful for the prophet to marry the “daughters of his paternal and maternal uncles and aunts”. In other words, his first cousins. But the second-last sentence “This is for you and not for the believers (at large)” prohibited this practice for all other Muslims. Why? Because of the potential health problems with cousin marriages, that are summarized in my article through the Charsadda tragedy Since cousin marriage was a common practice in pre-Islamic Arabia. – and not having received till then any guidance to the contrary — the prophet must have followed that prevailing practice in marrying Zainab.
    I would suggest that verse 33.50 was revealed after the Muhammad-Zainab marriage to put a stop to this practice. This prohibition must have had such an impact on the prophet that later, he did not even marry the daughters of his foster brothers who had been proposed to him (Umm Habib, Fakhita, and Umama bint Hamza). (
    According to Abdullah Yusuf Ali, Surah Al Nisa (Surah 4) was revealed after the Battle of the Trench. Let us now consider verse 4.23.
    4.23. Prohibited to you (for marriage) are: your mother daughters sisters father’s sisters mother’s sisters; brother’s daughters; sister’s daughters;` foster-mothers (who gave you suck) foster-sisters; your wives’ mothers; your step-daughters under your guardianship born of your wives to whom you have gone in no prohibition if you have not gone it; (those who have been wives of your sons proceeding from your loins; and two sisters in wedlock at one and the same time except for what is past; for God is Oft-Forgiving Most Merciful. (Surah Al-Nisa).
    Summarizing, to me, these Qur’anic prohibitions against cousin marriage underscore the scientific validity of these verses. If, however, we argue that cousin marriage is OK, then we are showing that Qur’anic verses are totally unscientific in that these promote a practice that science has demonstrated to bring significant grief to society.
    Which option do we want to take?

  • Syed N. Q

    September 10, 2020 - - 12:14 pm

    O prophet, We have made lawful for you all your wives whom you have given their dowers, and those (bondwomen) whom you own, out of the captives Allah has given to you as spoils of war, and daughters of your paternal uncle, and daughters of your paternal aunts, and daughters of your maternal uncle, and daughters of your maternal aunts, who have migrated with you, and a believing woman who offers herself for (marrying) the prophet without dower, if the prophet wishes to bring her into his marriage, these rules being exclusive for you, and not for the (rest of the) believers,-(surah Al ahzab)

    The special consideration given to prophet Muhammad s.a.w was marrying without dower.
    Islamic Shariah rules never proven on scientific bases, whether if Shariah goes totally against science, we’ll consider science as false.
    Cousin marriage is absolutely HALAL, all 4 imams are united on this point.
    Please don’t spread such blunder….!!!!
    Atleast refrain from fiqh when not qualified as islamic scholar(proper procedure learning of Quran and sunnah)
    Let Mufti(s) do their job.
    Jazakallah khair.

  • Saleem Ahmed

    September 11, 2020 - - 6:33 am

    Verse 33.50 unambiguously provided the prophet permission to marry his cousin; similarly, it equally unambiguously prohibited other Muslims from marrying their first cousins. It is not a matter of seeking clarification that we need to consult other authorities. If, on the other hand, we say that other Muslims are also allowed to marry their cousins, then we will be proving to the world that Islam is an unscientific religions which promotes a practice that has been found to carry many medical challenges. I draw your attention to the Charsadda tragedy in my article. On the other hand, if we underscore that the Qur’an prohibited this practice 1,400 years ago, which has only recently been found to be dangerous for humans, we will underscore how scientifically-advance the Qur’an is. Also consider on other point: Only one of the prophet’s 13 wives was his cousin; the other 12 were not even remotely related to him. So, which Sunnah do we follow? A sunnah related to one action of the prophet? Or one related to 12 actions of the prophet?

  • Syed N. Q

    September 11, 2020 - - 6:53 am

    Give any authentic Fatwa supporting your view which clearly says cousin marriage is prohibited for muslims from Saudi/ Deoband/ any trusted Mufti/ Dar- ul- Fatawa rather than putting simply scientific researches.

    What you claim to say prohibited is absolutely something never stated by any trusted Islamic school of thoughts, which means you need some concrete refrences and certification and definitely requires consultation.
    Scientific researches never considered in Shariah, it’s only Quran and sunnah.

    Not to offend but wrong interpretations are harming muslim ummah greatly.

  • Syed N. Q

    September 11, 2020 - - 8:00 am

    As per ur view if cousin marriage is prohibited in Islam, do you know what it means – lacs of muslims are committing ‘zina’ (major sin) for their whole married life and millions of people are born out of unlawful sexual relationships..and so on… Are you weighing its consequences..
    Are all scholars of Islam blind if such is the case.
    Think before you say anything halal / haram.

    Encouraging non-consanguinous marriages is absolutely FINE, but saying consanguinous marriage is prohibited is a total error.

    I am a MBBS doctor, I know the risk of congenital anomalies in newborns from consanguinous parents which is practically significant only for specific some inherited genetic disorders or if it is practised continuously for generations which was again discouraged by prophet Muhammad (pbuh).

  • Saleem Ahmed

    September 11, 2020 - - 4:10 pm

    (Response to Br. S.N. Naqvi). Yes, I know that my article suggests that “lacs of Muslims” have been in error in promoting and practicing cousin marriage. Thus, should we not we not help stop this practice, as soon as possible?

  • Saleem Ahmed

    September 11, 2020 - - 5:45 pm

    (Continuing my response to Br. S.N. Naqvi) I should also add I am also trying to prevent the thousands of future Muslims from being born blind, having congenital deformities, and other PREVENTABLE ailments that cousin marriages have been found to generate. Please look at your own relatives and friends suffering from these ailments. And you will probably see that, in many cases, there is a history of cousin marriages involved. Please don’t continue with this practice just as the Charsadda people are continuing because they feel “culture bound” to do so. We have to “swallow the bitter pill” and bring this practice to an end. As I mentioned in my article, I know of four people among my relatives who became blind in their middle ages, probably because of cousin marriages; and I know of three siblings who were born with such serious physical deformities that they have never walked. Now, only one of them is alive. She is in her sixties-seventies. Fortunately, she has one brother who was born “normal”. I applaud that brother who has been taking care of all three, now of his remaining affected sister. I shudder to think of what might happen to the sister if she outlives her brother.

  • Syed N. Q

    September 11, 2020 - - 8:07 pm

    Discouraging practice of cousin marriage is acceptable brother, you have reasons for it.

    Problem lies when you declare it’s prohibition (totally different from discouragement) which is not at all acceptable Br. Saleem Ahmed. All you state regarding ailments are true, which may provide ground to discourage the same but not for its Prohibition.

    We cannot put halal / haraam from our pocket if we dislike some of its part or other it’s Allah (s.w.t) who had declared what is halal and what is haraam no one can dare to alter them.
    Allah knows the best.
    Jazakallah khair

  • Saleem Ahmed

    September 12, 2020 - - 2:24 am

    5:17 PM (4 hours ago)
    to me

    I am quoting verse of surah Nisa which shows prohibited relations for muslims in which it does not include cousins brother.
    Which proves it’s halal .

    Saleem Ahmed
    7:50 PM (1 hour ago)
    to SYED, bcc: Saleem

    (My response to Br. Nimatullah): Verse 4.23 states: Prohibited to you (for marriage) are: your mother; daughters; sisters; father’s sisters; mother’s sisters; brother’s daughters; sister’s daughters; ,foster-mothers (who gave you suck); foster-sisters; your wives’ mothers; your step-daughters under your guardianship born of your wives to whom ye have gone in no prohibition if ye have not gone in; (those who have been) wives of your sons proceeding from your loins; and two sisters in wedlock at one and the same time except for what is past; for God is Oft-Forgiving Most Merciful.

    And verse 33.50 states: O Prophet ! We have Made lawful to thee Thy wives to whom thou Hast paid their dowers ; And those whom thy Right hand possesses out of The prisoners of war whom God has assigned to thee; and daughters of thy paternal Uncles and aunts, and daughters Of thy maternal uncles And aunts who migrated (From Mecca) with thee ; And any believing woman Who dedicates her soul To the Prophet if the Prophet Wishes to wed her ;— this Only for thee, and not For the Believers (at large) ; We know what We have Appointed for them as to Their wives and the captives Whom their right hands Possess ;— in order that There should be no difficulty For thee. And God is Oft-Forgiving, Most Merciful.

    Among relatives permitted for the prophet to marry but disallowed to other Muslims, are “daughters of thy paternal Uncles and aunts, and daughters Of thy maternal uncles And aunts. who migrated (From Mecca) with thee. And it adds: this (is) Only for thee, and not For the Believers (at large).

    So, my understanding is that marriage with these relatives is not permitted to all other Muslims. And “daughters of your paternal uncles and aunts and daughters of your maternal uncles and aunts are your cousins. Why are these relatives not mentioned in verse 4.23 but mentioned in verse 33.50, I cannot answer. My approach is to go by the (pardon the analogy), “least common denominator”. The prohibition in verse 33.50 is all that I need to follow, especially since no other verse abrogates it.

    Individuals are free to disregard this — as long as they understand the possible health challenges associated with cousin marriages discussed in my article. God knows best.


  • Saleem Ahmed

    September 12, 2020 - - 2:49 am

    Saleem Ahmed
    8:02 PM (1 hour ago)
    to SYED

    (My response to Br. Niyamatullah): I checked the translation of verse 33.50 by other notable translators, with the following results regarding what I have termed as “prohibition”: These are all messages to the prophet (regarding permission to him to marry his cousin, but underscoring that this was not for all other Muslims)::

    (This is) a privilege for thee, and not for other believers.

    ˹This is˺ exclusively for you, not for the rest of the believers.

    This permission is only for you and not for the other believers,

    (This is) a privilege for thee only, not for the (rest of) believers.

    Yusuf Ali
    This only for thee and not for the Believers (at large).

    REQUEST to Br. Niamat and others:
    Thus, please suggest what would be an appropriate alternative word to “prohibition: in this context. Thanks. Whether you call it a prohibition or use some “softer” word, is entirely up to you.

    Trying to quote some Muslim authority to back my position will not help because cousin marriage has been considered a “preferred” arrangement all along,; a sunnah which most people have tried to emulate. Apparently, people simply rely on the Muhammad-Zainab marriage as the Sunnah to follow, regardless of verse 33.50. Unfortunately, apparently, there was no apparent reason to dig into it. Now, there is. Please also remember that the prophet’s other 12 marriages were to non-relatives; to non-relatives, including to three Jewish women and two women who came from Christian backgrounds. So, which one should Muslims follow? May Allah guide us all. Ameen.


  • Saleem Ahmed

    September 12, 2020 - - 5:27 pm

    Regarding the concern that Muslims may have committed zina by marrying their cousins: One of the beauties of the Qur’an is that it requires that we understand the intention of any possible transgression. In the case of cousin marriage, since the intention of all those involved was NOT to violate a Qur’anic injunction but to honor what they thought was a sunnah, I would suggest that God, in all His magnanimity, may probably overlook this “transgression”; perhaps even applaud the individuals for their past unquestioned love to fulfil what they consider to be a requirements of their religion.
    But looking ahead: Now that they understand the implications of cousin marriages, their knowing violation might not be received the same way. I really feel sorry for those who might be in the final phases of planning a cousin marriage. I guess that this might be looked upon by Allah as having crossed the point of no return, and to proceed with it. And may Allah bless their intention. The only concern remaining with be regarding possible medical problems. At a minimum, they should undergo blood testing to weed out some possible problems. May Allah guide us all.

  • Dolores

    September 25, 2020 - - 6:58 am

    Regarding cousin marriages: Can Qur’an 49:13 ( O’mankind. We created you from a single (pair) of a male and a female, and made you into nations and tribes) be explained?

  • Saleem Ahmed

    September 25, 2020 - - 2:58 pm

    Thanks, Dolores, for your question. The historian Ibn Ishaq explains that this verse was revealed after the prophet had conquered Mecca (629 CE), without any resistance. Because there was fear among the Meccan people that he would take his revenge by punishing them for the years of persecution he had faced at their hands earlier, this verse was to allay their fears. The “creation from a single pair” refers to Adam and Eve, from whom humanity sprang. This verse underscores that the “haughtiness” with which the Quraysh tribe looked upon themselves was false pride; that all humans were equal in the eyes of God. Incidentally, scientists have determined that humanity started in Ethiopia, about 300,000 years ago. Thus, Adam and Eve were dark-skinned people; and so was all humanity for about 100,000 years till humans spread into Asia and Europe, where, the lower UV radiation gradually changed their skin pigmentation over the next 100,000+ years.
    The verse emphasizes the equality of all humanity and underscores that, in the eyes of God, the only difference between them is in their degree of righteousness. I think this clarifies that adherence to rituals (prayers, fasting, etc.) is meaningless without doing good deeds, such as honesty, justice, compassion, etc. In fact, the latter is preferred by God over the former. I will be discuss this further. Thanks.

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