Adoption And Issue Of Mahram
Please refer to the following video specifically from 2:06 onward https://youtu.be/53Ypm6mvAHQ
Surah An-Nissa Provides some guidance in this regard. We can derive from it logically which relationships are Prohibited(Mehram) and which are not. (Na-Mehram). The Adopted Children are also a category of Foster children. Since they are not biologically related to their Adopted Parents. Hence they are not blood children or born through union from their adopted parents. Foster: bring up (a child that is not one’s own by birth Adopt: legally take (another’s child) and bring it up as one’s own. (4:23) Forbidden to you are your mothers, your daughters, your sisters, your father’s sisters and your mother’s sisters, your brother’s daughters and your sister’s daughters, your milk-mothers, your milk-sisters, the mothers of your wives, and the stepdaughters – who are your foster-children , born of your wives with whom you have consummated the marriage; but if you have not consummated the marriage with them, there will be no blame upon you (if you marry their daughters). It is also forbidden for you to take the wives of the sons who have sprung from your loins and to take two sisters together in marriage, although what is past is past. Surely Allah is All-Forgiving, All-Compassionate.