This passage from the Tosefta is concerned with matters of inheritance, though this scenario could plausibly open a discussion on the status or lineage of the children of an Israelite woman, with either a gentile or a slave. This source teaches that a convert or a freed slave cannot bequeath assets to sons who were conceived with an Israelite woman prior to his conversion or manumission, respectively. With regard to freed slaves, this rule resembles the Roman law of inheritance, as applied to slaves and freedmen. As Henrik Mouritsen has noted, “In Roman law the slave, being socially ‘dead’ had no recognised parents or children. In the same way they had no civic persona, so they were also deprived of any familial identity, formally not being the child of their parents or parents of their children” (The Freedman, p. 37). Jane F. Gardner explains that “Freedmen … had no agnates, because as slaves they had had, in the eyes of the law, no recognized family relationships” (Family and Familia, p. 18).

The status of the convert, however, may be explained in the context of Roman laws regarding new citizens. As I have showed elsewhere, there are striking parallels between these rabbinic laws and the Roman legislation which also associates a father’s loss of paternal authority upon gaining citizenship with his children’s loss of status as heirs (including Gaius, Institutes, 1.93-94; 3.19-20). It therefore seems that tannaitic halakhah reflects an internalization of particular features of the status of new Roman citizens that were then applied to converts (Wilfand, “A Proselyte”). 

In our text, a son conceived by an Israelite woman and a gentile prior to his conversion is not considered an heir of his now converted father. The notion that a convert cannot bequeath possessions to sons who were born prior to his conversion appears in several rabbinic texts (see Sifre Numbers 4 and Mishnah Bava Qamma 9:11). Thus, when a convert or manumitted slave dies, his assets become the property of the first Israelite male to claim them.