Are the children of Jews and Christians considered children of fornication, even if they were born within a legitimate marriage in their religion, on the pretext that their religions are false and therefore their marriage contracts are void?

The Jews and Christians distorted and altered the Torah and the Gospel. Whatever parts of them were not distorted have been abrogated by the law of Muhammad, peace be upon him. The adherence of the People of the Book to their abrogated religion in their transactions and marriages makes their actions valid among themselves. Their children are not ruled to be illegitimate unless it is known that they conceived them through an illicit method according to their own religion. The evidence for this is Islam's affirmation of their lineage to their fathers, the establishment of the guardianship of the Kitabi father over his daughter, the validity of a Muslim's marriage to one of them, and inheritance among them.