Is it haram to marry your cousin?

Marrying your cousin is halal in Islam. The Quran gives a precise list of the relatives a person may not marry, and cousins are not on it. It then declares everyone beyond that list lawful, and in another verse it names cousins directly among the women the Prophet ﷺ could marry. He married his own first cousin, Zaynab bint Jaḥsh. The one caution the tradition and modern medicine both offer concerns health, and genetic counseling answers it well.

What does the Quran say about marrying your cousin?

Sūrat al-Nisāʾ lists the women a man may not marry: mothers, daughters, sisters, paternal and maternal aunts, nieces, foster mothers and foster sisters, mothers-in-law, stepdaughters, daughters-in-law, and two sisters at once (4:23). Then it says:

وَأُحِلَّ لَكُم مَّا وَرَآءَ ذَٰلِكُمۡ

“And lawful to you are all beyond these.”

Quran 4:24

The list includes aunts and nieces and stops there. A cousin, the child of an aunt or uncle, falls among those “beyond these.” The same rule applies, in mirror form, to a woman marrying her male cousin.

The Quran also names cousins directly. Addressing the Prophet ﷺ, it describes the women lawful for him to marry:

وَبَنَاتِ عَمِّكَ وَبَنَاتِ عَمَّـٰتِكَ وَبَنَاتِ خَالِكَ وَبَنَاتِ خَٰلَٰتِكَ

“And the daughters of your paternal uncles and paternal aunts, and the daughters of your maternal uncles and maternal aunts.”

Quran 33:50

All four kinds of first cousin appear in this one line.

Did the Prophet ﷺ marry his cousin?

He did. Zaynab bint Jaḥsh (may Allah be pleased with her) was the daughter of Umayma bint ʿAbd al-Muṭṭalib, the Prophet’s ﷺ paternal aunt. The Quran itself records their marriage (33:37), and Zaynab used to tell the other wives that their families had given them in marriage, while Allah had given her in marriage from above the seven heavens (Sahih al-Bukhari 7420). Her story, and the Prophet’s ﷺ other marriages, are told in How many wives did the Prophet have?

Marriage within the extended family has been common among Muslims from the first generation. ʿAlī ibn Abī Ṭālib, the Prophet’s ﷺ cousin, married Fāṭima, the Prophet’s ﷺ daughter. Cousin marriage was also common in Europe until recent times: Charles Darwin married his first cousin Emma Wedgwood, and Albert Einstein married his cousin Elsa.

What did the scholars say about cousin marriage?

All four Sunni schools and the Jaʿfari school agree that marrying a cousin is lawful. Some classical jurists gave advice about preference. Al-Shāfiʿī (d. 820) held that it is recommended for a man to marry outside his own clan, and later Shafiʿi scholars explained that marriage was meant to bind different families together. Ibn Qudama (d. 1223) recommended a bride from outside the family, saying her children would be stronger, and warned that a quarrel between spouses who are cousins can spread to the whole family and strain the ties of kinship.

Other scholars disagreed with even this advice. Taqī al-Dīn al-Subkī (d. 1355) rejected the Shafiʿi recommendation as lacking evidence, pointing to the marriage of ʿAlī and Fāṭima. A saying sometimes quoted against cousin marriage, “Marry outside the family, lest your children be weak,” is found in no hadith collection with a reliable chain, and the hadith scholar Ibn al-Ṣalāḥ said he found no reliable basis for the report attributed to the Prophet ﷺ discouraging marriage to close relatives.

The sound position is that cousin marriage is fully lawful, and that a family may weigh the practical advice of the jurists alongside the medical advice of today.

Are there health risks in marrying a cousin?

The children of first cousins have a somewhat higher chance of inherited conditions, because their parents are more likely to carry the same rare recessive genes. The risk is smaller than many people assume. A 2002 review led by Robin Bennett for the National Society of Genetic Counselors estimated the added risk of a serious birth defect or genetic disorder at 1.7 to 2.8 percentage points above the risk every couple carries. The risk rises when cousin marriage is repeated over several generations, or when a family already carries a known condition such as thalassemia or sickle cell disease.

Islamic law protects the health of the next generation as one of its objectives (maqāṣid al-sharīʿa, مقاصد الشريعة), and Muslim societies have acted on this. Saudi Arabia made premarital screening for sickle cell disease and thalassemia mandatory in 2004, and similar programs run in Bahrain, Qatar, the UAE, and Iran. A couple who are cousins can:

• See a genetic counselor before the wedding, especially if relatives have had inherited illnesses.
• Take a premarital blood test for the conditions common in their community.
• Make an informed choice together. Many cousin couples learn that their risk is low and marry with peace of mind; others learn about options such as prenatal testing.

Is consent still required?

Always. A cousin marriage arranged by families is lawful only when both the bride and groom freely agree. Pressure to marry a cousin to keep property or honor in the family has no place in Islam, and a marriage without the bride’s consent is invalid (Is forced marriage allowed in Islam?). The Prophet ﷺ gave a young woman the choice to annul a marriage her father had arranged without her consent (Sunan Abi Dawud 2096, graded sahih by al-Albani). Getting to know a prospective spouse with honesty and good manners is part of choosing well (Is dating haram in Islam?), and the wedding itself is described in What happens at a Muslim wedding?

Love within the family

When the choice is free and the families are at peace, a marriage between cousins can be a double blessing: a new home, and old ties of kinship made stronger. The Quran asks believers to be mindful of Allah “and of the ties of the womb” (Quran 4:1). May Allah bless every marriage made in His name, and grant the couple health, love, and righteous children.