I have a rather complex question. A girl I know has a father who was adopted at birth. The fat
her took on the family name of the family who adopted him, and has kept it ever since. As such, he passed it to his children.
Should the girl keep the family name of the father? Is it permissible for her to adopt the family name of her mother (the so-called maiden name) particularly as the mother’s family is ahl-ul-bayt or both?
What is prohibited is to give the notion to others that someone other than ones own biological father is their father, i.e. to attribute oneself to someone other than ones own father. It is related in a hadith in Sahih Muslim and other compilations that the Prophet Sallallahu alayhi wasallam said whoever attributed himself to someone other than his own father has committed and act of unbelief. This means someone who knowingly claims or gives the notion to people that he is the child of someone besides his real father.
So in the case in question, if the father’s situation was a similar one where people thought him to be the child of the adopting couple, then he needs to clarify to people that they were not his real parents. As for the daughter, there is no need for her to change her name, and she can not take her mother’s maiden name anyway because a person should be attributed to the father. Since she is known to be her father’s child there is no problem at all.
Another point to bear in mind here is that many groups of people, especially the African American community in the USA, have in many cases lost all bearings of their ancestry since they were given the surnames of the Europeans that subjugated them.
And Allah knows best.
Mufti Abdurrahman ibn Yusuf