Question Summary:
Is it permissible for the child to take the mother’s surname?

Question Detail:

I would like to ask is there any ruling in Islam which states that a child has to take the surname of the father e.g fardh? As in would it be permissable for the child to take the mothers surname? If the child does take the mothers surname then would there be any sin?

Answer :

In the Name of Allāh, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
According to Shari‘ah, a person should be attributed to his ancestral lineage through his father. Allah Ta‘āla mentions in the Qur’ān:
ادْعُوهُمْ لِآبائِهِمْ هُوَ أَقْسَطُ عِنْدَ اللَّهِ
Call them by [the names of] their fathers; it is more just in the sight of Allah. [33:5]
This verse was revealed when the foster son of Rasūllāh Sallallāhu ‘Alayhi Wa Sallam, Hadhrat Zaid bin Hārithah was being referred to as Zaid bin Muhammad. This practice was common amongst the Arabs as they treated their adopted children as their own; in lineage, inheritance, marriage, etc. However, when the above mentioned verse was revealed, the Sahābah would call him Zaid bin Hārithah.
However, it is permissible for the child to adopt the mother’s surname provided that the child’s lineage to the biological father is well known amongst the people. This is to assure that there is no confusion with regards to the child’s lineage. There are many examples where Sahābah, Tāb‘ieen and ‘Ulamā were given the names of their mothers/grandmothers. Such as, ‘Abdullāh ibn Umme Maktūm radhiyallāhu ‘anhu and ‘Abdullah ibn Umme ‘Abd (‘Abdullāh Ibn Mas‘ūd) radhiyallāhu ‘anhu, etc.  
 
 
And Allah Ta‘āla Knows Best
Fahad Abdul Wahab
Student Darul Iftaa
USA
Checked and Approved by,
Mufti Ebrahim Desai                                                                                                                                                                                                                
www.Daruliftaa.net