The breastfeeding that prohibits marriage takes place only if
the baby has five times of suckling or more during the first two years of their life. The description of one suckling is as follows: A baby holds a breast and sucks milk. If it leaves it to take a breath or to be moved to another breast, then this is to be counted as one suckling, and so forth until five times of suckling are counted. If the times of suckling are less than five, even if they are four times of suckling, then this breastfeeding does not prohibit marriage. Mentioning the women forbidden for marriage, Allah (Exalted be He) says,
...your foster mothers who gave you suck, your foster milk suckling sisters.
It is reported by Al-Bukhari and Muslim that the Prophet (peace be upon him) said
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.
It is related by Muslim
`A'ishah (may Allah be pleased with her) said: "Amongst what was sent down of the Qur'an was 'ten known times of suckling forbid marriage. Then it was abrogated by 'five known times of suckling'. When the Messenger of Allah (Part No. 21; Page No. 101) (peace be upon him) died, it was recited as Qur'an." It is authentically reported that
`Aishah (may Allah be pleased with her) also related that Allah's Messenger (peace be upon him) said:
One suckling or two do not make (marriage) unlawful.
If these conditions of breastfeeding are met, the breastfed child becomes a milk-child of the woman who breastfed him/her; all her children become his/her milk-siblings; and her husband becomes his milk-father. Thus all the Mahrams (unmarriageable relatives) of the husband become Mahrams to the breastfed child and all his (the husband's) children become milk-siblings to the breastfed child, whether those belonging to the husband through the breastfeeding woman or through any of his other wives. The consequences of the mentioned breastfeeding are that marriage will be prohibited between the breastfed child and both the Mahrams (unmarriageable relatives) of the breastfeeding woman and the Mahrams of her husband, even those belonging to him through other wives. It is Mustahab (desirable) to maintain the ties of kinship with them both through salutation or any other kind of lawful greeting. May Allah grant us success. May Allah's Peace and Blessings be upon our Prophet, his family and Companions!