It is very difficult to come to an understanding of the following statements:
1. The earlier doros matured quickly
2. The Halachos Moshe L'Sinai discuss checking for two hairs at twelve, not
at six or seven or three.
The Gemara says b'tzalel was 13 since he's called ish, meaning he is not ish until 13, but he's still a katan. Why is he a katan if he can already have children?
Neil Blavin
Everything you said is true, we just need to put it together: The fact that we cannot have children before reaching the age of Gadlus is not because only one who is Halachically classified as a "Gadol" can have children, but rather because we are not physically mature until we reach the age of Gadlus. The two happen to come together. However, the age of Gadlus is set by a Halachah l'Moshe mi'Sinai and not by the fact that we cannot have children, and therefore even the Doros ha'Rishonim, who were able to have children before the age of Gadlus, were still not considered Gedolim until the age of 13.
D. Zupnik