Is a young Muslim man obligated to marry a Christian girl who became pregnant by him and gave birth to a daughter, and is the child attributed to him, especially given the possibility of the mother converting to Islam?

Allah has permitted a Muslim man to marry a woman from the People of the Book, provided she is chaste, as stated in the Almighty's words: "And [lawful in marriage are] the chaste women from among the believers and the chaste women from among those who were given the Scripture before you, when you have given them their due compensation."

Therefore, it is not permissible for a young man to marry a Christian girl with whom he committed adultery. And a child born from adultery is attributed to its mother and cannot be attributed to him.