Three sucks do not prohibit marriage
20-9-2010 | IslamWeb
Question:
Assalamu alaikum.I gave breast feeding to my co sister's child with the intention my children and my husbands children become Mahrams.I gave 3 times milk.But now I heard I had to give 5 sucklings.Does that mean my children and their children will not become Mahrams?Our intention was as such.But it was only ignorance that we gave 3 sucklings.So because of ignorance does it become invalid?Does suckling make my elder daughter mahram if this is valid as suckling was given to my cosisters first son who is younger to my daughter.Also they have a second son.Does he also become Mahram to my daughter or not if valid? Jazakhallah Khair
Answer:
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad 
is His slave and Messenger.
First of all, it should be mentioned that the scholars differed in opinion in regard to the number of suckling times that prohibit marriage, so the Hanafi, Maaliki Schools of jurisprudence and Ahmad (in one narration from him) and many Companions and Taabi’is are of the view that little or much suckling renders a couple forbidden to each other even if it were one sucking, since the condition of suckling that prohibits marriage is that the milk reaches the stomach of the child no matter what its amount is. Their evidence is the Saying of Allaah about women to whom marriage is prohibited (which means): {your [milk] mothers who nursed you, ….}[Quran 4:23]
On the other hand, the Shaafi’i and the Hanbali Schools of jurisprudence – according to their correct opinion – are of the view that less than 5 suckling times does not make a couple forbidden to each other: this is narrated from ‘Aa’ishah, Ibn Mas’ood and Ibn Az-Zubayr 
and it is the view of ‘Atta’ and Taawoos 
and their evidence is what is narrated by ‘Aa’ishah who said: “It has been revealed in the Quran that ten clear (attested) sucklings make the marriage unlawful, then it was abrogated by five sucklings and Allaah’s Messenger, sallallaahu ‘alayhi wa sallam, died and it was before that time (found) in the Quran and recited by Muslims.”
However, this is the preponderant opinion that we adopt here in Islamweb and we consider 5 sucklings a condition to prohibit marriage because the Hadeeth is a clear text for that. Therefore, suckling the son of the brother of your husband three sucks does not make him a suckling brother of your children.
Nevertheless, he should not marry any of your daughters in the future as a way of taking into consideration the opinion of those who are of the view that they three suckings are enough to prohibit marriage.
Moreover, it should be noted that if we assume that suckling the son of the brother of your husband is of the kind that prohibits marriage, then it is only that son who becomes a suckling brother of your children whether they are younger or older than him. As regards his brothers and sisters who did not suckle from you, then they do not become suckling brothers of your children.
Also, suckling the older son if it took place when he was more than two years old, then this suckling is of no effect and it does not make him a suckling brother of your children because the suckling that prohibits marriage is that which takes place before two years of age; the evidence is the Hadeeth which reads: “Suckling does not prohibit marriage except which penetrates the (i.e. serves as a nutrition for the child) from the breasts, and it is prior to weaning.” and the Hadeeth which reads: “Suckling is only valid if it takes place before two years of age.” [Ad-Daaraqutni]
At-Tirmithi 
said: “Most of the scholars from among the Companions and others adopted the opinion that suckling does not prohibit marriage except that which takes place before two years of age, and the suckling that takes place after two years of age does not make one forbidden for marriage at all.” For more benefit, please refer to Fatwa 99499.
Allaah Knows best.