If an older or adult person or a person of any age or infant child or child of any age drinks the milk of any kind and type of haram animal which gives milk, i.e. monkey, cats etc, is the foster relationship through milk established by doing so?

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.

The milk of non-human females, from all animals, regardless of whether it be of those whose meat we are forbidden to eat or those whose meat is lawful for us to eat, does not establish the relationship of Radhaa‘ (foster relation by breastfeeding from the same female) and does not lead to a Mahram (permanently unmarriageable) relation between those who drank it.

Mukhtasar Khaleel Al-Maaliki, when speaking about the breastfeeding subject to the rulings of Radhaa‘, reads, “It is to drink a woman's milk, even if she is dead or young.” The interpreters of this book said, “What is meant by the woman is the human female; and the milk of an animal or a jinn does not lead to the Mahram relation between those who drank from it; so if a boy and a girl drink from the same sheep or from the same female of any other kind of animal, then this does not make them forbidden to marry each other (i.e. become Mahram to each other).”

Al-Mudawwanah of Imaam Maalik reads, “I said: If two girls are fed from the milk of the same animal, do they become sisters? He said: The prohibition due to breastfeeding can only be from the milk of the daughters of Aadam [i.e. from women].”

Ibn Qudaamah from the Hanbali School of jurisprudence, said, “The prohibition (due to breastfeeding) is not spread with the milk of a non-human female at all; so if two boys breastfeed from the milk of the same animal, they do not become brothers, according to the majority of the scholars.”

Therefore there is no consideration for breastfeeding from an animal in the Shariah.

On the other hand, the breastfeeding to which the rulings on Radhaa‘ apply is that which happens to an infant within the first two years of age – or within a month or two months, according to some scholars. As for the breastfeeding of an adult person, then the view of the majority of the scholars is that it is of no effect, and the rulings on breastfeeding do not apply to it, according to most scholars.

The breastfeeding of some of the early Muslims while they were adults was a special concession for them as a way of removing the difficulty that affected some of them, as understood by the wives of the Prophet and was adopted by the leading Imaams and all the Muslim scholars.

Bidaayat Al-Mujtahid, authored by Ibn Rushd Al-Maaliki, reads:

“The scholars agreed that the breastfeeding that leads to making the persons who breastfed from the same woman Mahram to each other is that which happens during the first two years of age only. They (scholars) differed in opinion about the breastfeeding of an adult person: Maalik, Abu Haneefah, Ash-Shaafi'i and all the scholars of Fiqh said: The breastfeeding of an adult person does not lead to any Mahram relation. Daawood (Ath-Thaahiri) and the Thaahiriyyah (those who interpret the texts literally and refuse to accept clear analogy) held that the breastfeeding of an adult person leads to the Mahram relation, and this was the view of ‘Aa’ishah.”

Allah knows best.