Shaykh Ahmad an-Najmee was asked the following question:
May Allah be good to you, this questioner from France says: there is a man who entered Islam and he does not have a father because his father and mother were not married [i.e. he is an illegitimate child]. So is it allowed for this Muslim to name himself the son of Adam or son of Ibrahim?
“It is allowed for him. He can name himself with any name”.
Faisal Ibn Abdul Qaadir Ibn Hassan