If You Were Breast-fed by Your Grandmother, it is Forbidden For You to Marry Your Maternal Uncle's Daughter

Question :

I was breast-fed by my grandmother my mother's mother, so is it permissible for me to marry the daughter of my maternal uncle my mother's brother from the same mother and father?

Answer:

The breast-feeding which brings about prohibition is five breast-feedings or more during the first two years of life.

One breast-feeding is when the child takes the breast and sucks milk from it, then leaves it. Then if he returns to it and sucks milk from it, it is considered a second breast-feeding, and so on.

So if you were breast-fed by your grandmother five times or more in the aforementioned manner, you have become a brother to your maternal uncle through breast-feeding, according to the Words of Allah, Most Glorified:
"Forbidden to you (for marriage) are: your mothers."

And: "your brother's daughters, your sister's daughters."

And according to the narration confirmed from the Prophet ﷺ, in which he said:
"That which is forbidden due to birth is forbidden due to breast- feeding."

And according to the narration confirmed from 'A'ishah, may Allah be pleased with her, in which she said: "It was revealed in the Qur'an that ten known breast-feedings caused prohibition, then it was abrogated by five known breast-feedings. Then the Prophet ﷺ died and the matter remained thus."

If your breast-feeding from your grandmother took place less than five times as mentioned, or outside the first two years, it is permissible for you to marry your maternal uncle's daughter.