Why did Adam father Sheis only at such a late age?
Maharal (Be'er ha'Golah, Be'er 6, Ch. 16, p. 136): Hashem made procreation in order to ensure the world's continuity. Adam, as the handiwork of Hashem, would have a very long life, and so it was unnecessary for him to have children at the young age at which people do today. 1
Maharal (ibid.): So too for the following generations, both before and after the Flood; their childbearing age was high relative to today, but it fluctuated, as did their lifespan. Only today, when the lifetime is stable around 70, is the age of maturity stable at 12 years.
What are the implications of "Vayoled bi'Demuso ke'Tzalmo"?
Seforno: It implies that Sheis was a greater Tzadik than both Kayin and Hevel, since even Hevel did not bring a Korban until he took his cue from Kayin. 1
Ramban #1: In fact, this refers to Kayin and Hevel too, and the Torah mentions it only here in connection with Sheis, since Mankind descended from him and not from them.
Ramban #2: It implies that Sheis, unlike Kayin, was perfect physically (in strength and appearance) like his father Adam.
Targum Yonasan: It implies that Sheis resembled his father in both appearance and behavior. 2
Eruvin 18b: It implies that, until now, Adam 'gave birth' to various kinds of demons, who did not share the same image as him. 3
Avos de'R. Nasan: It implies that, just as Adam was created circumcised, 4 so too, was Sheis born circumcised.
How will we reconcile the current Pasuk, which states that Adam called his son 'Sheis,' with Pasuk 4:25, which states that Chavah named him?
Oznayim la'Torah: Initially, they thought that since she gave birth to the baby, it belonged to her. 1 It is only after the Torah mentions the "Sefer Toldos Adam" (5:1), that they were given to understand a man's close connection to his children. That is why Adam now asserted his rights - by agreeing with the name that Chavah chose, and officially naming him Sheis. 2
QUESTIONS ON RASHI
Rashi writes: "'[Adam was] a hundred and thirty years [old]' - For this long, he had abstained from [intimacy with] his wife". Perhaps he never abstained, but it was only now that he fathered more children?
Gur Aryeh: We learned that Hashem now added onto Adam's desire (Rashi in 4:25), in order to bring about that he have more children. 1 If not for this extra desire, Adam would not have fathered more children, for until now he had been abstaining.
Sifsei Chachamim: Otherwise, seeing as Kayin and Hevel were born on the day that Adam was created, why did it take so long for him to have another child.
Gur Aryeh (to 4:25); refer to 4:25:2.2:1 . If Adam had been regularly fulfilling Mitzvas Onah in any case, Chavah would have conceived even without the added impetus of desire.
