What is the ruling regarding Lady Aisha suckling Salim, what was his relation to her, and how many adopted children did the Prophet (peace be upon him) have?

Breastfeeding an adult does not establish mahramiyyah (prohibition of marriage), nor does it have any effect. This is the view of the majority of scholars, based on the Prophet's (peace be upon him) saying: "There is no prohibition from breastfeeding except what ruptures the intestines in the breast, and was before weaning." As for the breastfeeding of Salim, the freed slave of Abu Hudhayfah, it was a special case for Salim and cannot be generalized. Aisha (may Allah be pleased with her) differed with the majority of the Companions and the Mothers of the Believers on this matter.

The Companions, the Tabi'un, and the Four Imams have all agreed that breastfeeding an adult does not establish mahramiyyah, based on the Prophet's (peace be upon him) saying: "Breastfeeding is only from hunger," and "There is no suckling except that which makes the flesh and blood grow."

The Prophet (peace be upon him) did not adopt anyone other than Zayd ibn Harithah, and that was before the prohibition of adoption in Allah's (the Most High) saying: "Call them by [the names of] their fathers; it is more just in the sight of Allah."