First of all, we’d like to state that Islam is keen that every child is to be named after his or her biological father. Thus, a husband may adopt his wife’s kids, in the sense of caring for their well-being and securing an appropriate upbringing for them, the child should retain their biological father’s name and not take his name. This is because Islam commands that we call people by their proper names, not by false names.
The eminent Muslim scholar and renowned Da`iyah, Sheikh `Abdel Khaliq Hasan Ash-Shareef, states: “Adoption in the sense of changing one’s identity and lineage for a false lineage is absolutely prohibited in Islam; but at the same time, we are allowed to adopt them in the sense of taking them under our wing for providing both physical and spiritual care for them. So, we are not allowed to adopt them in the sense of officially attributing them to our name. This is the forbidden adoption in Islam. However, we are permitted to take care of them and to bring them up according to the ethics and morals of Islam while expecting great reward from Allah.”