Prohibited Degrees in Muslim Marriage

Consanguinity (Nasab) | Affinity (Musaharat) | Fosterage (Riza) | Unlawful Conjunction

1. Overview of Prohibited Relations

A Muslim may not marry every person. The law identifies specific categories of relations with whom marriage is forbidden. Classical Muslim jurists divide these prohibitions into two broad groups — absolute (permanent) and relative (temporary or conditional). The absolute group operates in every school of Islam; the relative group exhibits inter-school variation and is curable (by removing the impediment).

Quranic Source — Sura Nisa 4:22-24

The Four-Fold Classification

2. Consanguinity (Nasab) — Blood Relationship

Nasab refers to blood relationship. The Quran forbids marriage with seven categories of blood relations of a man (Sura Nisa 4:23). The prohibition is reciprocal — a woman is likewise forbidden to marry the corresponding male relations. The rule applies without any distinction between relationships of full-blood and half-blood; and without any distinction between legitimate and illegitimate descent (illegitimate descent being equally an impediment to marriage though not to inheritance).

Prohibited Blood Relations (for a Man)

1. His mother, grandmother (paternal or maternal), great-grandmother, and ancestresses however high.
2. His daughter, granddaughter, great-granddaughter, and descendants however low.
3. His sister — whether full, consanguine (same father) or uterine (same mother).
4. His paternal aunt and maternal aunt, and aunts of ancestors however high.
5. His brother's daughter, sister's daughter, and their descendants however low.

Note the symmetric list for a woman: her father, grandfather, son, grandson, brother, paternal and maternal uncles, brother's son, sister's son, and their descendants.

Rationale

The classical rationale combines biological (avoidance of inbreeding and the genetic harm it causes), moral (preservation of the family structure and its affectional bonds) and theological (Quranic injunction that does not require further rationale). Modern scientific understanding of consanguineous marriage supports the biological rationale.

3. Affinity (Musaharat) — Relationship Through Marriage

Musaharat is the relationship created by marriage (not by blood). Three Quranic prohibitions fall under this head:

A. Wife's Mother (Mother-in-law)

A man may not marry his wife's mother, or her grandmother and ancestresses, at any time — whether during the subsistence of the marriage or after its dissolution. The prohibition arises on the very contract of marriage to the wife; it does not require consummation.

B. Wife's Daughter (Step-daughter)

A man may not marry his wife's daughter from a previous union (step-daughter), provided the marriage with her mother has been consummated. Sura Nisa 4:23 carefully adds the qualifier: "step-daughters under your guardianship born of your wives unto whom you have gone in — but if you have not gone in unto them, there is no sin upon you." If the man has divorced the wife before consummation, he may marry her daughter.

C. Father's Wife (Step-mother)

A man may not marry his father's wife (step-mother). This prohibition is absolute and arises immediately on the father's marriage, irrespective of consummation. Sura Nisa 4:22: "And do not marry those women whom your fathers married, except what has already passed."

D. Son's Wife (Daughter-in-law)

A man may not marry his son's wife or his son's widow. Sura Nisa 4:23: "and the wives of your sons who are from your own loins." The qualification 'from your own loins' has a classical-juristic purpose — it excluded the adopted son's wife from the prohibition, because pre-Islamic Arabia had the custom of adoption creating full filial ties, which Islam abolished.

Symmetry for Women

A woman may not marry her husband's father, her husband's son (step-son, if mother has consummated marriage with father-in-law), her son's husband (son-in-law) — the reciprocal of every male-side prohibition.

Effect of Dissolution of Underlying Marriage

The affinity prohibitions do not disappear merely because the underlying marriage has ended by death or divorce. Once affinity is established, it is permanent. A man divorced from his wife can never marry her mother, and a man whose son has died or divorced cannot marry his son's widow.

4. Fosterage (Riza) — Milk Relationship

Riza is the relationship created by suckling — when a woman nurses a child, the child becomes her 'milk-child' and takes on a network of milk-relations that parallel the blood-relation network. The Prophet Muhammad said: "What is prohibited by blood is prohibited by fosterage" (Bukhari and Muslim). Riza is therefore a powerful and extensive prohibition.

Essentials of Fosterage

1. The child must be nursed within the age-limit for foster-status. The Hanafi view is 2.5 lunar years; the Shafi, Maliki and Ithna Ashari view is 2 lunar years; some minority views go up to 5 years.
2. The nursing must consist of the woman's own milk (not mixed or substitute).
3. The quantity must be sufficient to nourish — classical views differ: one full feeding (Hanafi / Maliki); five separate feedings (Shafi, based on a Hadith of A'isha); ten feedings (some minority views).
4. The milk must reach the child's stomach — mere touch of the nipple does not suffice.

Prohibited Milk-Relations

• Foster-mother — the woman who nursed the man, and her ancestresses (milk-grandmothers).
• Foster-sister — any other woman who suckled from the same foster-mother.
• Foster-daughter — any woman nursed by the man's wife (making her his milk-daughter).
• Foster-aunt, foster-niece — reciprocal to the milk-mother's siblings and children.
• Foster-mother's sister (foster-aunt); foster-mother's daughter (foster-sister) — fully parallel to blood consanguinity.

The foster-father's wife, other than the actual nursing woman, is not automatically within the prohibition — only the woman who actually nursed the child creates the prohibition.

Limits of Fosterage — The Hanafi Relaxation

Hanafi law recognises certain relaxations not accepted by other schools:

• A foster-mother's sister is not prohibited in all Hanafi views.
• Very limited suckling (less than one full feeding) is held not to establish fosterage by some Hanafi jurists.

The Shafi school takes the stricter view — any suckling (above the minimum quantitative threshold) establishes the prohibition.

Ayesha's View — Five Feedings

A'isha, the Prophet's wife, is reported to have said that the Quran originally prescribed ten feedings as constituting fosterage, later abrogated to five; this is the Shafi position. Other schools treat it differently — Hanafis accept any suckling above minimum; Malikis require satisfaction of the child's hunger on one feeding.

5. Unlawful Conjunction (Jam-i-Muharramat)

The fourth category is relative — it is a prohibition not on marrying a specific person absolutely, but on marrying two persons simultaneously. The Quranic basis is Sura Nisa 4:23: "and [forbidden is] to combine two sisters."

Rule

A man cannot be married to two women simultaneously who — had they been of opposite sexes — would have been within the prohibited degrees of consanguinity. Thus he cannot marry:

• Two sisters at the same time (the Quranic prohibition).
• A woman and her paternal or maternal aunt simultaneously.
• A woman and her niece (brother's daughter or sister's daughter) simultaneously.

How the Prohibition is Cured

The prohibition operates only so long as both women are within the marital bond. If one of the marriages is dissolved by death or divorce, and iddat (if applicable) is completed, the man may marry the other. Thus the prohibition is relative — unlike nasab, musaharat, and riza which are absolute.

School-wise Consequence of Breach

• Hanafi — the second marriage is fasid (irregular); curable by divorcing the first wife and completing her iddat.
• Shafi, Maliki, Ithna Ashari Shia — the second marriage is batil (void) from the beginning.

Fifth Wife Rule

A Muslim man may have up to four wives simultaneously (Sura Nisa 4:3). A fifth wife is within the category of jam-i-muharramat in a different sense — not because of relationship but because of numerical limit. The fifth marriage is fasid (Hanafi) or batil (other schools). If he divorces one of his wives and she completes iddat, he may marry another.

6. Other Matrimonial Bars

A. Iddat

A woman during iddat (waiting period after divorce or widowhood) cannot contract a new marriage. The prohibition is temporary — it ends when the iddat is completed. Marriage during iddat is fasid (Hanafi) or batil (Shia / Shafi).

B. Subsisting Marriage

A Muslim woman cannot contract a second marriage while the first subsists — classical Islam prohibits polyandry absolutely. The second marriage is batil in all schools. This is the mirror image of the man's right to up to four wives.

C. Difference of Religion

Classical position on inter-religious marriage:

• Sunni: a Muslim man may marry a Kitabiyya woman (Christian, Jewish — 'People of the Book'); may not marry an idol-worshipper.
• Shia Ithna Ashari: permanent marriage with Kitabiyya generally disfavoured; muta (temporary) marriage permitted.
• Muslim woman with non-Muslim man: batil (void) in all schools classically.

Sura Baqarah 2:221: "Do not marry polytheist women until they believe… and do not give [your women] in marriage to polytheist men until they believe." The Sura Maidah 5:5 permits Muslim men to marry Kitabiyya.

D. Triple Divorce Without Intervening Marriage (Halala)

If a man has divorced his wife three times (irrevocably), he cannot remarry her until she has married another man, the marriage has been consummated, and that man has divorced her of his own accord. This is the rule of halala under Sura Baqarah 2:230 — a temporary bar that can be removed only by this specific procedure.

VII. Leading Indian Cases

1. Aizunnissa Khatoon v. Karimunnisa, (1895) 23 Cal 130 (FB)

Full Bench of Calcutta High Court. A Sunni man had married his wife's sister during the subsistence of the first marriage (jam-i-muharramat). The Court held the second marriage was fasid — not batil — in Hanafi law, and therefore curable. This is the leading authority on jam-i-muharramat in Hanafi practice.

2. Amir Mian v. Ismile Begum, ILR (1941) 15 Luck 665

Lucknow Bench. Held that consanguinity, affinity and fosterage prohibitions are absolute and make the marriage void in all schools — not merely irregular. The specific issue was a marriage with wife's daughter (step-daughter) after consummation with the wife.

3. Ayesha Bibi v. Ebrahim Haji Jacob, (1909) ILR 33 Bom 1

Bombay. Discussed the fosterage rule and the quantum of suckling required under Hanafi law. Held that actual suckling in the infant period establishes the prohibition.

4. Hashim Ibrahim v. Soda Bibi, AIR 1930 Bom 52

Affinity prohibition held to survive dissolution of the first marriage — the widower could not marry his deceased wife's mother even after the wife's death and completion of iddat.

5. Syed Mohd. Saad Andalib v. Vidhi Bindal, 2024 (Allahabad HC)

Recent Allahabad High Court ruling which reaffirmed that inter-religious marriage between a Muslim man and a Hindu (idol-worshipper) woman under Muslim personal law is fasid, not batil, while noting that such marriages are valid if solemnised under the Special Marriage Act, 1954. A modern illustration of the doctrine.

VIII. Consolidated Comparison Table

IX. Exam Corner

Practice Questions

1. Classify and discuss the prohibited degrees of marriage in Muslim law. (15 marks)
2. Write a detailed note on the law of fosterage (riza) in Muslim law. (10 marks)
3. Distinguish between absolute and relative prohibitions on marriage in Muslim law. (10 marks)
4. Examine the rule against unlawful conjunction (jam-i-muharramat) with reference to the Aizunnissa Khatoon case. (10 marks)
5. MCQ: The Quranic verse that prohibits marrying two sisters simultaneously is — (a) Sura Nisa 4:3 (b) Sura Nisa 4:23 (c) Sura Baqarah 2:221 (d) Sura Maidah 5:5. Answer: (b).

X. Conclusion

The prohibited degrees in Muslim marriage reflect a coherent scheme grounded directly in the Quran: three absolute prohibitions (nasab, musaharat, riza) that operate in all schools, and one relative prohibition (jam-i-muharramat) that is curable. The absolute prohibitions mirror the fundamental moral intuitions expressed in the Quran — prohibition of incest, protection of the family structure, and extension of family bonds through the powerful symbolism of milk-relationship. The relative prohibitions accommodate changing factual situations — divorce, death, and iddat — while preserving the core principles.

For the judicial aspirant, three mnemonic aids consolidate the topic. First, remember Sura Nisa 4:23 as the 'master verse' — naming fourteen categories of forbidden relations. Second, the four-fold classification (nasab, musaharat, riza, jam-i-muharramat) gives a complete taxonomy. Third, the distinction between absolute and relative prohibitions determines the legal consequence — batil (void, permanent) vs fasid (irregular, curable). Every MCQ and every essay on the subject reduces to applying these three tools.

XI. Frequently Asked Questions

Q1. What are the three absolute prohibitions in Muslim marriage?

Consanguinity (nasab — blood relationship), affinity (musaharat — relationship through marriage) and fosterage (riza — milk relationship). All three operate in every school and make the marriage void (batil) if breached.

Q2. Can a Muslim man marry his sister-in-law (wife's sister)?

Not while the first marriage subsists — this is the rule of jam-i-muharramat (unlawful conjunction), based on Sura Nisa 4:23 prohibiting two sisters simultaneously. If the first wife dies or is divorced and her iddat is completed, he may marry her sister. In Hanafi law, the second marriage is fasid while the first subsists; in other schools it is batil.

Q3. Can a Muslim marry his step-daughter?

Only if the marriage with the step-daughter's mother was not consummated. If the marriage was consummated, the step-daughter is permanently prohibited by affinity (Sura Nisa 4:23). If not consummated, marriage with her is permissible after divorce of the mother.

Q4. What is the fosterage rule?

When a woman nurses a child, a set of milk-relations is created that parallel blood-relations. Marriage between milk-relations is prohibited. The Prophet said: "What is prohibited by blood is prohibited by fosterage." Age-limit for fosterage is 2.5 lunar years (Hanafi) or 2 years (Shafi/Maliki/Shia).

Q5. Can a Muslim woman marry a Hindu man?

Classically, no — such a marriage is batil in all schools. However, the parties may solemnise marriage under the Special Marriage Act 1954, which is secular and inter-religious. Under SMA, the marriage is valid regardless of religion; succession follows the Indian Succession Act 1925.

Q6. Can a Muslim man marry a Christian woman?

Yes, under classical Sunni law — a Muslim man may marry a Kitabiyya (Christian or Jewish woman) because Sura Maidah 5:5 expressly permits it. Shia classical view is stricter (permitting only muta). In India, such marriages may be solemnised under Muslim personal law or, more commonly now, under the Special Marriage Act.

Q7. What happens if a marriage violates an absolute prohibition?

It is batil (void ab initio). No legal consequences flow from it — no dower, no mutual inheritance, and the children are classically illegitimate (though modern Indian courts have progressively mitigated the harsh legitimacy consequences).

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