conversion bath even before he is born. In the next responsum (#224, column 196b) he gives as the opinion of Aaron Halevi and the Tosfot that the unborn child is completely a proselyte.
Thus with regard to children conceived as Gentiles and born after the mother is a Jewess(born in qedusha) Isserles says that the term"convert" is not to be applied to them(Dargei Mosheh to Tur, Hoshen Mishpat 33) that they are not converts(but they are born Jews ). This is cited by Shach op. cit. with approval as the established opinion. That is to say, that while there will be some disagreement as to the child's relationship to previous children of its mother in a possible levirate situation, or whether or not it is too closely related to them to be permitted to be a witness in a Jewish court in cases affecting them(since relatives may not be witnesses) there is no question that the child(though not conceived"in holiness" but born"in holiness”) is obligated to fulfill the commandments because it is fully Jewish .