Why does the Torah see fit to inform us that Yosef's two sons were born before the famine began?
Rashi (citing Ta'anis 11a): We learn from here that a man is forbidden to be intimate with his wife during a time of famine. 1
Rashbam: Because Yaakov would later draw a distinction between Efrayim and Menasheh, who were born before he arrived close to the beginning of the years of famine, and other sons, whom Yosef bore later. 2 And this Pasuk clarifies his statement there.
Ramban (to 48:15): It implies that other children were born to him after the famine. 3
Why did the Torah teach here about the birth of Yosef's sons?
Ohr ha'Chayim: After telling his success in gathering grain, it tells his success in children. Also the names he gave indicate contentment - Hashem made me forget my toil, and has made me flourish, i.e. with children, wealth and honor.
QUESTIONS ON RASHI
Rashi writes: "'Before the year of famine arrived' - [We learn] from here that one may not engage in marital relations during years of hunger." But the Gemara (Ta'anis 11a) says that someone who has not yet fulfilled the minimum requirement of "Peru u'Revu" (Bereishis 1:28) is permitted to do so?
Gur Aryeh #1: Yosef had a daughter as well 1 prior to the years of famine, and thus had already fulfilled the Mitzvah of Peru u'Revu. 2
Gur Aryeh #2:It was known that this famine would have a finite duration (of seven years). Even someone who had not yet fulfilled Peru u'Revu could wait until the famine would conclude, and then father children. 3
Gur Aryeh #3: While it would not have been strictly forbidden for Yosef to procreate during the famine (since he had not yet fulfilled the Mitzvah), it would have been a blemish on Efrayim and Menashe, had they been born out of a waiver of a prohibition. The Torah therefore informs us that they were born before the famine began.
According to Beis Hillel, the Mitzvah to procreate is minimally fulfilled by having both a son and a daughter (Yevamos 62b).
Gur Aryeh challenges this answer; the count of Yaakov's descendants would then have totaled more than 70.
Gur Aryeh: Whereas in the case of a famine of unknown duration, he should not abstain, lest he be left childless. (Note that Hadar Zekenim to 26:8 suggests the opposite approach; refer to 26:8:152:3. (CS))
Rashi writes: "One may not engage in marital relations during years of hunger." Didn't Levi father Yocheved during the years of famine; she was born upon their entry to Egypt (Rashi to 46:15, see Bava Basra 120a)! (Gur Aryeh adds, wasn't Yitzchak intimate with his wife Rivkah during a famine (Rashi to 26:8)?)
Da'as Zekenim #1, Hadar Zekenim #1, Moshav Zekenim, Gur Aryeh: The Gemara (Ta'anis 11a) tells us that someone who has not yet fulfilled the minimum requirement of "Peru u'Revu" (Bereishis 1:28) is permitted to do so during a famine. Whereas Yosef held that he already fulfilled Peru u'Revu through two males; 1 Levi held that a male and female are required (Tana'im argue about this - Yevamos 61b). Neither Yitzchak nor Levi had a daughter as yet, so they were permitted.
Da'as Zekenim #2, Hadar Zekenim #2: The Isur is only for a Navi. Yosef knew that there will be seven years of famine, so he was forbidden. Levi was permitted, for he thought that the famine [could] end tomorrow. 2
Riva: Yocheved was conceived after Levi found out that Yosef is alive (and can feed everyone); they delayed seven or nine months until they came to Egypt. 3
Riva citing Chizkuni: Yosef needed to refrain, for he thought that his family is in pain. 4 Levi was permitted. He did not need to be concerned for Yosef [or for Nochrim in pain - Moshav Zekenim, Ohr ha'Chayim],
Tosfos (to Ta'anis 11a): It is mere Midas Chasidus to refrain. Yosef was a Chasid; 5 the other Shevatim were not. 6
Tosfos Rid (to Bava Basra 120a): The Torah was not yet given. We learn from one who fulfilled (Yosef), but we do not infer Heter from one who did not fulfill (Levi).
Ohr ha'Chayim: The Gemara permits one who did not yet fulfill Peru u'Revu. Indeed, Yosef was permitted for this reason; the verse cannot teach about him, so it teaches about others [who fulfilled Peru u'Revu].
Ha'amek Davar: The Isur is only during a famine of extinction. In Eretz Yisrael there was merely a famine of Batzores; vegetables and herbs grew for people to eat. If nothing was growing, like in Egypt, they would have died!
Perhaps Yosef agreed that also a daughter is needed, and he already had one! A Midrash (refer to 43:34:3:1) implies that Menasheh was his only child before Efrayim, but it is not a proof. (PF)
Ta'anis 11a implies that the Isur applies even nowadays, without Nevu'ah! (PF)
It is only a four- or five-day journey to Egypt (Midrash Tanchuma Miketz 6)! Perhaps 'ba'Derech' is from when they began preparing to descend. Or, Yaakov's family traveled much slower than normal, due to babies or young animals. Rashbam (to Bava Basra 120a) and R. Gershom (loc. cit.) say that Bein ha'Chomos means within Egypt itself (perhaps she was born months after they arrived in Egypt), but Riva implies like Rashi (46:15), that it is at the entrance. (PF)
Ohr ha'Chayim: Yocheved was conceived in the first year of famine. Yaakov still had food; he sent his sons only due to Mar'is Ayin.
Also refer to 37:2:7.2:2.
Ohr ha'Chayim: The Gemara implies that it is a true Isur! Also, it says about Levi "l'Ish Chasidecha" (Devarim 33:8)! Even if this applies to his Shevet, surely his Shevet reflects their source (Levi)!
