Son marries daughter-in-law: incest?

In your response to question Id#600, Abdur-Rahman Mangera answered that you can marry your step sister, if they had different parents but The eminent Muslim scholar Sheikh Yusuf Al-Qaradawi wrote about this matter in his well-known book, The Lawful and the Prohibited in Islam. It is permanently haram for a Muslim man to marry a woman who belongs to one of the following categories: 1. The father's wife, whether divorced or widowed. During the period of jahiliyyah (pre-Islamic era of Ignorance) such marriages were allowed. Then Islam prohibited them, for once a woman is married to a man's father she acquires the status of his mother, and this prohibition is out of honor and respect for the father. Moreover, as this inviolable prohibition leaves no room for sexual attraction between the son and his step-mother, they are able to develop a relationship of respect and honor. 2. The mother, including the grandmothers on both sides. 3. The daughter, including the granddaughters from the son or daughter. 4. The sister, including the half- and step-sisters. 5. The paternal aunt, whether she is the real, half-, or step-sister of the father. 6. The maternal aunt, whether she is the real, half-, or step-sister of the father. 7. The brother's daughter, i.e., his niece. 8. The sister's daughter, i.e., his niece. All these female blood-relatives are a man's muharramat and he is mahram to his corresponding female relatives. Marriage to any mahram whomsoever is permanently prohibited. The reasons for this prohibition are as follows. a. Entertaining any sexual thoughts concerning such close relatives as one's mother, sister, and daughter is instinctively abhorrent to human nature; there are even certain animals which avoid mating with such closely-related animals. The respect a man feels for his aunts is like the respect he has for his mother, and likewise uncles are regarded as fathers. b. Since the family must live together in intimacy and privacy but without incestuous relations, the Shari`ah intends to cut at the roots of any sexual attraction among such close relatives. c. Since there is natural love and affection among such close blood relatives, the intent of the Shari`ah is to expand the circle of love and kinship by prohibiting incest and thereby directing the man's search for women outside the family. Thus each marriage extends the sphere of love, bringing new people within this ever-expanding network of affection: (And He has put love and mercy between you) (Ar-Rum 30:21). d. The natural sentiments of love and affection between a man and the above-mentioned female relatives must be kept strong forever. If marriage were permitted between such relatives, it would cause jealousies, dissensions, and the disruption of families, destroying the very sentiments of love and affection which give cohesiveness and permanence to the family structure. e. The offspring of marriages to such close blood relatives would most probably be defective and weak. Moreover, if physical or mental defects are present in the members of a family, they would become more pronounced among the children of such marriages. f. The woman needs someone to champion her rights and support her case against her husband, especially when relations between the two of them become strained. If those women who could defend her became rivals, how would this be possible? Now I am confused because I really need to know the answer to this question. Can you please clarify this matter and explain the meaning of Sura Al Nisa 4: 22-24.

In the name of Allah, Most Compassionate, Most Merciful,

The verse of Sura al-Nisa quoted by you is as follows. Allah Most High says:

“Prohibited to you [for marriage] are your mothers, your daughters, your sisters, your paternal aunts, your maternal aunts, brother’s daughters, sister’s daughters, your mothers who suckled you, your sisters through suckling, mothers of your wives and your step-daughters under your care who are born of your women with whom you have had intercourse, - though if you have had no intercourse with them, there is no sin on you - , and the wives of your sons from your loins, and that you combine two sisters [in wedlock], except what has passed. Surely, Allah is Most-Forgiving, Very Merciful.” (Qur’an 4/23)

In the above verse, Allah Most High cites “sisters” as being from amongst those with whom marriage is prohibited. The exegetes of the Qur’an (mufassirun) state that the prohibition of marrying one’s sisters includes marrying one’s own real sister, one’s half-sister from the same father but different mother (ukht allati), and one’s half-sister from the same mother but different father (ukht akhyafi). (See for example: Tafsir al-Kabir of Imam al-Razi, 4/25)

However, when a man and woman have different parents altogether, i.e. they have separate fathers and mothers, then they are not considered step-brothers and sisters to each other. As such, they are not included within the prohibition of marrying one’s own sister.

This is the reason why the renowned Hanafi Jurist, Imam al-Haskafi (may Allah have mercy on him), states:

“…As far as one’s father’s [previous] wife’s daughter [i.e. his ex-wife’s daughter from a previous marriage, and not one’s father’s daughter with her] or son, [marriage with them] is permitted.” (See: Radd al-Muhtar ala al-Durr al-Mukhtar 3/31)

The reason for this is clear – both, the man and woman, do not have any blood ties between them. They both have separate fathers and separate mothers, and as such, they cannot be considered step-brothers and sisters to one another.

This permissibility of marriage between them is proven from the statement of Allah Most High in the verse following the one mentioned above, where Allah Most High says:

“…All [women], except these, have been permitted for you to seek [to marry]…” (Qur’an 4/24)

And Allah knows best

Muhammad ibn Adam al-Kawthari