If the milk reaches the child’s stomach by a means other than direct suckling, it carries the same legal ruling as breast-feeding. Thus, if the milk is dripped into the infant’s mouth or nose, or he drinks it from a vessel or the like, it is treated as nursing, because it provides the same nourishment—on condition that this occurs five separate times.
As for the marriage impediment created by nursing: whenever a woman gives an infant under two lunar years five or more sucklings, the child becomes her son in regard to the prohibition of marrying her, the permissibility of his looking at her and being alone with her, and he is her maḥram. Allah the Exalted says: “and your mothers who nursed you” (Qur’an 4:23). He does not become her son for the rest of the rulings: she is not obliged to maintain him, there is no mutual inheritance, he is not liable to pay blood-money on her behalf, nor may he act as her guardian. Lineage is stronger than nursing; therefore nursing only carries the same weight where there is explicit textual evidence—namely, the prohibition of marriage and the related matters of maḥram status, lawful gaze, and seclusion.
The nursling likewise becomes the child of the man to whom the milk is attributed—whether because she conceived from him, or because he had intercourse with her through a valid marriage or something akin to it—for in these situations the pregnancy is ascribed to him, and the nursing is a branch of that. Accordingly, the nursling is counted as his child only in the rulings mentioned for the wet nurse: the prohibition of marriage, permission to look and be alone, and maḥram status, but not in any other rulings.
Those who are maḥram to the one to whom the milk is attributed—his fathers, children, mothers, grandfathers, grandmothers, brothers, sisters, their children, paternal uncles and aunts, and maternal uncles and aunts—also become maḥram to the nursling. Likewise, the maḥrams of the wet nurse—her fathers, children, mothers, sisters, paternal uncles, and so forth—are maḥram to the nursling.
Just as the prohibition applies to the nursling, it also extends to his descendants