Fatwas of Ibn Baz>Volume 22>Book on Breastfeeding>Effect of breastfeeding is specific to the breastfed baby: 168-
The prohibition produced by breastfeeding is confined to the breastfed child:
Question: There are two sisters; each has a number of children. The first breastfed her niece many times till she was sated and the second breastfed her nephew till he was sated up. How does this breastfeeding affect marriage between these maternal cousins?
Answer: Breastfeeding affects the breastfed baby only, not its siblings. It becomes a milk-child of the woman, who breastfed him, and of her husband. He also becomes a milk-brother of her male and female children. However, the blood siblings of the child, who are not breastfed by her, do not become her children as she only breastfed their brother. The Prophet (peace be upon him) stated: Milk relationships are equal to blood relationships in rendering marriage unlawful i.e. whatever prohibited due to blood relationships is also prohibited by milk relationships. The breastfeeding that results in the prohibition of marriage should be five or more during the first two years, as the Prophet (peace be upon him) said: “No breastfeeding (creates the relationship of Mahram: unmarriageable relatives), except that which is in the (first) two years (of infancy).”
The Prophet (peace be upon him) also said: (Al-Bukhari, Sahih, Book on testimonies, no. 2647; Muslim, Sahih, Book on breastfeeding, no. 1455; Al-Nasa’y, Sunan, Book on marriage, no. 3312; Abu Dawud, Sunan, Book on marriage, no. 2058; Ibn Majah, Sunan, Book on marriage, no. 1945; and Al-Darimy, Sunan, Book on marriage, no. 2256.) “Breastfeeding relationship is only established when milk is the only food (of the child).”
It is narrated that `Aishah (may Allah be pleased with her) said: It was revealed in the Qur’an that ten clear times of suckling prohibit marriage then it was abrogated (and substituted) by five clear times of suckling, and the Prophet (peace be upon him) died while it was so. (Related by Muslim in his Sahih (authentic) Book of Hadith and by Al-Tirmidhy in his Al-Jami` and this is Al-Tirmidhy’s wording) May Allah grant us success.
Fatwas of the Permanent Committee>Group 1>Volume 21: Breastfeeding>Kaffarah>Breastfeeding>A child breastfeeding five times during his first two years is her son: Fatwa no. 15018:
Question: A one-and-half-year-old baby drank the breast milk of his aunt that was discharged in a cup to get rid of. Would it be permissible for this child to marry his aunt’s daughters?
Answer: Breastfeeding that affects marriageability must take place in the first two years of the baby’s life and must be for five times or more. One breastfeeding is counted when the baby holds the breast and sucks milk from it. If he releases the breast, to take a breath or move to the other breast, then holds it and sucks milk again, this is the second time and so on until they become five times. If they are less than five, even by one, this does not affect marriageability. Allah (Exalted be He) says when specifying Mahrams (spouse or unmarriageable relatives): …your foster mother who gave you suck, your foster milk suckling sisters, The Prophet (peace be upon him) said in the following Hadith, which was agreed upon by Al-Bukhari and Muslim: “Relations due to breastfeeding forbid what blood relations do (regarding marital affairs).” Also Imam Muslim related on the authority of `Aishah (may Allah be pleased with her) that she said: It had been revealed in the Qur’an that ten clear times of breastfeeding affect marriageability, then it (i.e. this ruling) was abrogated (and substituted) by five clear times of breastfeeding. Allah’s Messenger (peace be upon him) died and it (i.e. this ruling) was recited in the Qur’an (i.e. the ruling had been settled as such).” If the child was breast-fed for five times or if he drank the breast milk from a vessel for the same number of times, he would become his aunt’s son by breasting and a brother by breastfeeding to all her sons and daughters. If they were less than five times of breastfeeding, even by one, the aunt would not be his mother by breastfeeding. In case there was any doubt about the times of breastfeeding, whether they were five or less, then the basic rule would be that they were less than five and, thus, this would not affect marriageability. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.
Member: Deputy Chairman Chairman `Abdul-`Aziz Al Al-Shaykh `Abdullah ibn Ghudayyan `Abdul-Razzaq `Afify `Abdul-`Aziz ibn `Abdullah ibn Baz