Islam strongly encourages taking in and raising a child who has no one — the Prophet ﷺ said, "I and the one who sponsors an orphan will be in Paradise like this," holding up his index and middle fingers (Sahih al-Bukhari 6005, and Sahih Muslim 2983: "the one who sponsors an orphan, whether of his own kin or another's") — but it forbids the legal fiction in which the child's lineage is erased and replaced with the adopting family's: "Call them by [the names of] their fathers; that is more just in the sight of Allah" (Quran 33:4-5). So the child keeps his own name and lineage, is told the truth about it, does not automatically become a mahram to the household, and does not inherit as a biological child would — though the family may gift him during their lifetime and leave him up to one third of the estate by bequest (wasiyyah). If the child is taken in while still nursing (within the first two years) and is breastfed by the foster mother — five separate feeds according to the Shafiʿis and Hanbalis, and even a single feed according to the Hanafis and Malikis — radaʿah establishes a real mahram relationship, which is how many families resolve the hijab and seclusion difficulty. Fostering in this Islamic form — kafalah — is among the most rewarded acts in the religion, provided the truth of the child's lineage is preserved.
Q&A · Youth & Parenting
Can a Muslim family adopt a child, and what are the rules?
Evidence — the daleel
On deen2u
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.