Is a sister born of zina obligated to honor her biological father who never inquired about her, and to demand financial support from him? Is it permissible for her to call him "my father"? Is she obligated to inform official authorities and people about the truth of her lineage, or should she keep the matter a secret to avoid embarrassment?

Scholars unanimously agree that a child is attributed to the husband of the adulteress, the owner of the marital bed, and not to the adulterer. This is based on the Prophet's (peace be upon him) saying: "The child is for the bed, and for the adulterer is the stone." The child remains attributed to the owner of the marital bed unless the husband repudiates him through lian. Therefore, the pregnancy found with the mother is attributed to the father and not to the adulterer. The sister mentioned is the daughter of the father and the sister of the questioner by lineage. All Islamic rulings derive from this, and she is his sister, entitled to all the rights of a sister. As for her mother having repented from adultery, Allah accepts the repentance of those who repent.