What is the Shariah ruling on the marriage of a young man and woman who committed zina (fornication/adultery) and the girl became pregnant by him, and on the marriage in which the families of the girl and the boy intervene to preserve the honor of the family and the fetus? And what is the Shariah ruling on those who participated in this process?

It is not permissible for a young man to marry a pregnant woman who conceived through adultery until she gives birth, so that the water of adultery does not mix with the water of marriage. Furthermore, the fetus has no relation to the adulterer in terms of lineage. If they were to marry before she gives birth, people would ignorantly attribute the child to him, leading to the child being exposed to the man's mahram (definition) relatives and inheriting from him, even though he is not his son.

Both young people must repent sincerely and increase their seeking of forgiveness and performing righteous deeds. After the woman gives birth and repents, it is permissible for the young man to marry her if he wishes. However, he is not allowed to claim the child as his own, because the child is not legally his father's. That which is legally nonexistent is like that which is physically nonexistent, in accordance with the Almighty's saying: "Call them by [the names of] their fathers; it is more just in the sight of Allah. But if you do not know their fathers, then they are your brothers in religion and your protectors."