Bava Batra

But let him reply to him [that our Mishnah speaks of the case] where he said, 'After she will have born [the child'!  — R. Huna follows his own view. For R. Huna said: [A child] does not acquire ownership  even [where the father had said].  'after she  will have born [him]  'For. [it was stated.] R. Nahman said: If a person conveys possession. through the agency of a third party. to an embryo.[the latter] does not acquire ownership. [If however, he said].]  'After she will have born'.  [the child] does acquire ownership. But R. Huna said: Even [where he said]. 'After she will have born'. [the child] does not acquire ownership. R. Shesheth however said: Whether he used the one, or the other expression.  [the child] acquires ownership. Said R. Sheshet: Whence do I derive this? — From the following:  If a proselyte died  and Israelites plundered his estate; and [subsequently] they heard that he had a son or that his wife was pregnant. they must return [whatever they have appropriated].  [If]. having returned everything they subsequently heard that his son died or that his wife miscarried, he who took possession the second [time]  has acquired ownership;  but [he who took possession] the first [time] has not acquired ownership. Now, if it could be assumed [that] an embryo does not acquire ownership why should they  need to take possession a second time? They have, surely. already taken possession once! Abaye [however] said: An inheritance which comes [to one] under the ordinary laws of succession  is different  Raba said: There  it is different,  because at first  they  were really uncertain of the legality of their acquisition.  What [practical difference is there] between them?  There is [a difference] between them [in the case] where a report was brought  that he  died, while [in fact] he was not dead. and after that he died. Come and hear: 'A babe [who is] one day old inherits and transmits  [From this it follows that only] one [who is] one day old [may inherit]  but not an embryo! — Surely R. Shesheth had explained  [this as meaning]: He  inherits the estate of his mother to transmit [it]  to his paternal brothers;  hence, only [then when he is] one day old but not [when] an embryo.What is the reason?