What is the ruling of Islamic law concerning a man who was adopted by his parents, and has come to know that he is the son of zina (fornication/adultery)? Is he obligated to change his lineage and search for his biological parents? What is the ruling on his adoption in the first place? And will the son of zina enter Paradise?

Adoption is forbidden in Islam. The child born of adultery is attributed to his mother and has full legal rights towards her. It is not permissible for him to search for the man who committed adultery with his mother, nor is he ever attributed to him, due to the saying of the Prophet, peace and blessings be upon him: "The child is for the bed, and for the fornicator is the stone." It is not permissible for the adopted child to be attributed to the adoptive parent and his wife. Official documents must be changed if possible. If this is difficult or would lead to harm, there is no sin, provided that the lack of attribution is made clear as much as possible. The child born of adultery bears no sin due to the actions of his parents, as Allah Almighty says: "And no bearer of burdens will bear the burden of another." Hadiths that condemn the child born of adultery are not authentic, or they are interpreted in a different sense.