How is the child of zina not attributed to his father, when he is of his loins, even if the two fornicators repent and marry, and have other children together?

Adultery is one of the gravest sins, and it is impermissible for two adulterers to marry each other except after repentance and istibra' (ensuring no pregnancy). The majority of scholars hold that a child conceived through adultery is not attributed to the adulterer but only to the mother. However, some scholars have permitted the adulterer to marry the woman pregnant by him, and that the child is attributed to him as long as the woman is not the bed (wife) of another man, and no one disputes his paternity of the child.