What is the ruling on a Muslim woman cohabiting with a Christian man without a lawful contract, then her marriage to a Muslim man, and does she become permissible for him, and what is the ruling on the children she bore from her Muslim husband?

The fornicator must repent, feel remorse, and resolve not to return to the sin. She should also increase her good deeds, as fornication is a major sin and a grave offense, and its punishment in this world is flogging or stoning. However, sincere repentance transforms bad deeds into good ones.

Her marriage to a Muslim is valid if it occurs after her repentance and after ascertaining that she is not pregnant from fornication through one menstrual cycle; otherwise, it would be unlawful. The benefit of ascertaining this is to ensure she is not pregnant from fornication.

As for the ruling on children, if a child is born less than six months from the date of marriage, he is not legally attributed to the husband. If he is born after six months or more, he is attributed to the husband and considered his son.