Is it permissible for one of two men who were suckled by the same woman to marry the sister of the other, if one of them was over two years old [at the time of suckling]?

The suckling of these two men is not without one of two scenarios:

1. They both suckled from a foreign woman who is not their mother: It is permissible for each of them to marry the sister of the other, because their suckling does not affect their siblings from other than this woman. 2. One of them suckled from the other's mother: The one who suckled becomes a brother to the sons and daughters of this woman, and it is forbidden for him to marry the sister of his brother from her, because she is his suckling sister. As for the brother of this girl, it is permissible for him to marry the sister of this brother's sister from another woman.

Conditions for valid suckling: It must occur within the first two years (hawlain) of the suckling child's life. If it extends beyond that, the preponderant opinion is that it is not considered valid.