brooklyn19, actually breast milk is kosher. An infant is allowed to breast-feed even from a non-Jew although it is not recommended because it is mitamtem halev. Moshe Rabbainu refused to feed from mitzri women because the mouth that was destined to speak with the shechina shouldn’t drink from a mitzri. The Halacha applies this to every Jew. There are two reasons given, one by R’ Yaakov Kaminetzki and one by R’ Shach (I can’t remember which is which). One is that every parent is michuyav to bring up their children as if they were Moshe Rabbeinu because everyone has the ability to be a gadol like Moshe. The other reason is that just as Moshe spoke to the shechina we all speak to Hashem every day when we daven and say brachos so it is improper for a Jew to breast-feed from a goy.
It is assur for an adult to drink directly from the breast (it is comparable to drinking from a sheretz) but it is muttar to drink (and parve) once it is separated.