By contrast, it is permissible for a man to marry the daughter of his paternal uncle, the daughter of his paternal aunt, the daughter of his maternal uncle, and the daughter of his maternal aunt, no matter how many generations lie between them.

It is not lawful for him to marry a girl born to a wife with whom he has consummated the marriage—that is, his step-daughter—nor may he marry anyone descended from that wife’s children, male or female. Likewise, it is unlawful for him to wed a woman whom any of his children or grandchildren, however remote, has previously married, whether or not that marriage was consummated and whether the father or grandfather died while still married to her or divorced her.

As a general rule, whenever a woman is forbidden to you, her daughter is also forbidden, with four exceptions: the daughter of your paternal aunt, the daughter of your maternal aunt, the daughter of your son’s wife, and the daughter of your father’s wife.

If, out of ignorance, a man marries any of the women who are categorically forbidden to him, the contract is annulled; neither spouse inherits from the other, and the woman is entitled to no mahr (dower) at all if intercourse has not taken place, not even half of the mahr. Should they have consummated the marriage and both of them are excused on account of their ignorance, she receives the full mahr that was stipulated. If only one party is deemed excused, the ḥadd (prescribed penalty) is waived for that person alone. Whenever the ḥadd is waived, any child born of the union is legally affiliated to the father. If the woman is subjected to the ḥadd, she is not entitled to a mahr.

A man is also forbidden to have relations with any woman whom his father, grandfather, son, or grandson has had sexual intercourse with by right of ownership, for female slaves in this respect are treated exactly like wives. According to Imam Mālik, even kissing, intimate touching undertaken for pleasure, or contact with the genital area renders the woman unlawful to the son just as actual intercourse does. Another report from him, however, states that kissing alone does not create such a prohibition; only full intercourse does.