Is Marriage with a Foster Sister Permissible? A Qurʾān and Ḥadīth Based Ruling
Source: Aḥkām wa Masāʾil – Nikāḥ ke Masāʾil, Volume 1, Page 317
We are two real brothers. My elder brother has five daughters, and I myself have two sons. My wife and my brother’s wife are real sisters. On one occasion, my wife breastfed one of my elder brother’s daughters. Now my question is: Can my younger son marry my brother’s younger daughter? Please provide complete guidance on this matter in the light of the Qurʾān and Ḥadīth.
Al-ḥamdu lillāh, waṣ-ṣalātu was-salāmu ʿalā Rasūlillāh, Ammā Baʿd!
Allah ﷻ says in the Qurʾān:
﴿وَأُمَّهَٰتُكُمُ ٱلَّٰتِيٓ أَرۡضَعۡنَكُمۡ وَأَخَوَٰتُكُم مِّنَ ٱلرَّضَٰعَةِ﴾
(al-Nisāʾ: 23)
"And your mothers who nursed you, and your foster sisters (are forbidden to you in marriage)."
The Prophet ﷺ said:
«اَلرَّضَاعَةُ تُحَرِّمُ مَا تُحَرِّمُ الْوِلَادَةُ»
(Ṣaḥīḥ al-Bukhārī, Kitāb al-Nikāḥ, Bāb: Wa-ummahātukum allatī arḍaʿnakum)
"Breastfeeding makes unlawful the same relations that blood relations make unlawful."
❀ Therefore, marriage between your son and that girl will not be permissible.
❀ Because by the bond of Riḍāʿah, they are regarded as brother and sister.
If your wife breastfed your brother’s daughter five or more times within two years of her age, then that girl is a foster sister to your sons. In such a case, marriage between them is ḥarām (forbidden) in Sharīʿah.
ھذا ما عندي والله أعلم بالصواب
Source: Aḥkām wa Masāʾil – Nikāḥ ke Masāʾil, Volume 1, Page 317
Background of the Question:
We are two real brothers. My elder brother has five daughters, and I myself have two sons. My wife and my brother’s wife are real sisters. On one occasion, my wife breastfed one of my elder brother’s daughters. Now my question is: Can my younger son marry my brother’s younger daughter? Please provide complete guidance on this matter in the light of the Qurʾān and Ḥadīth.
Answer:
Al-ḥamdu lillāh, waṣ-ṣalātu was-salāmu ʿalā Rasūlillāh, Ammā Baʿd!
Allah ﷻ says in the Qurʾān:
﴿وَأُمَّهَٰتُكُمُ ٱلَّٰتِيٓ أَرۡضَعۡنَكُمۡ وَأَخَوَٰتُكُم مِّنَ ٱلرَّضَٰعَةِ﴾
(al-Nisāʾ: 23)
"And your mothers who nursed you, and your foster sisters (are forbidden to you in marriage)."
The Prophet ﷺ said:
«اَلرَّضَاعَةُ تُحَرِّمُ مَا تُحَرِّمُ الْوِلَادَةُ»
(Ṣaḥīḥ al-Bukhārī, Kitāb al-Nikāḥ, Bāb: Wa-ummahātukum allatī arḍaʿnakum)
"Breastfeeding makes unlawful the same relations that blood relations make unlawful."
Sharʿī Explanation of the Issue:
- If your wife breastfed your brother’s daughter within two years of age, and the child nursed five times or more, then that girl becomes the foster daughter of your wife.
- Consequently, your son and that girl will become foster siblings.
❀ Therefore, marriage between your son and that girl will not be permissible.
❀ Because by the bond of Riḍāʿah, they are regarded as brother and sister.
⚖ Important Note:
- If breastfeeding took place after two years of age, or if the child nursed less than five times, then the matter would differ and would require further detailed investigation.
Conclusion:
If your wife breastfed your brother’s daughter five or more times within two years of her age, then that girl is a foster sister to your sons. In such a case, marriage between them is ḥarām (forbidden) in Sharīʿah.
ھذا ما عندي والله أعلم بالصواب
