What is the ruling if the father has intercourse with the son's female slave, assuming the son had not previously had intercourse with her?
Chapter on What is Prohibited to Marry and Combining Between Them and Other Matters
Al-Mughni
Book of Marriage
Primary text
If the father has intercourse with his son's female slave, and the father had legal possession (*qabd*) of her, and the son had not previously had intercourse with her, then the child belongs to the father, and the female slave belongs to the father. The son has no claim over her or the child. This is because the father is permitted to take from his son's wealth anything in excess of what is needed for the son's sustenance, provided the father has no immediate need for that property.
Supporting text
If the son had already had intercourse with her, then she does not become an *umm walad* to the father because intercourse with her would then be forbidden to the father (as she is effectively promised to the son, or the father is interdicted from taking her) and the pregnancy would be considered conceived through a relationship with a slave belonging to one's offspring, potentially rendering the fetus illegitimately conceived relative to the father's claim.