Answered by Ustadh Tabraze Azam
Question: I have breastfed my brother’s eldest daughter. Will my son become a mahram to other kids (meaning siblings of the child I breastfed) as well? Will my son become mahram to my brother’s wife?
I pray that you are in the best of health and faith, insha’Allah.
The general case is that the child who is nursed is considered to be akin to a member of the family, yet this ruling is not applicable to the siblings of the nursed child.
As an example, Zaid and Khalida have two children: Sara and Ahmad. Khalida nurses her friend’s son Dawud. Dawud is now considered to be a milk brother to both Sara and Ahmad. However, Dawud’s sister, Mona, remains unrelated to the family and could marry Ahmad if she so wanted.
[Kasani, Bada`i al-Sana`i fi Tartib al-Shara`i]
I hope that is clear, insha’Allah.
Please also see: Adoption and Creating a Mahram Relationship Through Nursing
And Allah alone knows best.
في البدائع للإمام الكاساني: ويجوز للرجل أن يتزوج أخت أخيه لأبيه من النسب وصورته منكوحة أبيه إذا ولدت ابنا ولها بنت من زوج آخر؛ فهي أخت أخيه لأبيه فيجوز له أن يتزوجها، وكذا يجوز للرجل أن يتزوج أخت أخته من الرضاع وهذا ظاهر اهـ.
Checked & Approved by Shaykh Faraz Rabbani
This answer was collected from Seekersguidance.org. It’s an online learning platform overseen by Sheikh Faraz Rabbani. All courses are free. They also have in-person classes in Canada.