לזכות ר' מאיר שמחה בן לאה לברכה והצלחה בכל מעשי ידיו
If one has children when he is a goy and then converts, R' Yochanan holds that he fulfills the mitzvah of peru urivu, because he is now a Jew with children. Reish Lakish says that he is not fulfilling the mitzvah because גר שנתגייר כקטן שנולד דמי and he is like a new person so the children he had as a goy don't count [Yevamos 62a].
We rule like Rav Yochanan that he fulfills the mitzvah. The Shulchan Aruch [1/7] says that the children must convert as well [based on the Rambam Ishus 15/6].
Tosfos [based on the understanding of the Beis Shmuel] argues that the children need not convert in order for the father to fulfill the mitzvah of peru urivu.
If the son didn't convert but the grandson did - it would seem that even the Rambam would agree that the convert is yotzei the mitzvah.
The gemara says that if one has children as an eved, and then he is freed with them, he doesn't fulfill the mitzvah until he has children after his release, since the children he had as an eved are not related to him.
If a goy has a child with a Jewish woman and then converts, he has also not fulfilled the mitzvah because this child upon being born is not related to him.
What is the din if a goy impregnated a goya and then they converted before the child was born, does he fulfill the mitzvah according to Tosfos even if the child does not convert and according to the Rambam if he converts?
It would seem that he is not mekayeim the mitzvah, because when the child is born, he is not related to his father. It is true that the fetus was related to his [gentile] father, but that doesn't necessarily create a fulfillment of peru urivu. [It appears that a fetus IS related to his father as we see from the din that a fetus inherits his father. But when born he is not related to his now Jewish father].
According to this, if a goya was impregnated by a goy, should they convert now even though they will lose out on the mitzvah of peru urivu [if they have no more children afterwards other than the one extra child they need in order to fufill the mitzvah according to Beis Hillel who says that you need to have a boy and a girl] or maybe he should wait until the child is born and then convert, thus fulfilling peru urivu. This way - the child is related to him when he is born, and after conversion he fulfills the mitzvah of peru urivu according to Rav Yochanan.
Similarly, what is the halacha if a person wants to convert before Pesach but he has no matza to eat. Should he wait until after Pesach to convert?
In pashtus - he should not push off being a Jew and missing out on matza is not such a problem because he is considered an אונס.
If a goy wants to convert before succos - he should probably buy the arba minim before his conversion [if he won't have time afterwards]. Can you imagine - a goy in Boro Park buying a mehudar set of arba minim??:-)
If a goy wants to convert before succos - he should probably buy the arba minim before his conversion [if he won't have time afterwards]. Can you imagine - a goy in Boro Park buying a mehudar set of arba minim??:-)
[Rav Avraham Genechovski ztz"l]
