To adopt a child is a very commendable thing to do. Islam does not prohibit adoption in any way. In this regard, two courses can be adopted:
a) To adopt a child during his suckling age so that he can drink the milk of the mother who has adopted him. In this case, the child will be her foster-son and there will be no difference between him and the mother's real children in any manner. He will possess the same rights in all affairs (eg inheritance) as the real children possess.
b) To adopt a child when he is past his suckling age. In this case, he will not be the legal or real son of the parents who have adopted him. When he grows up he must be told about his real parents. After disclosing the real parents, the new father can even add his name to the child’s name. The parents who have adopted him can of course address him as "son". However, the child will not inherit their wealth after them, unless of course they make a will in his favour.