R. Yochanan says that it is a Halachah l'Moshe mi'Sinai that a father may make his son into a Nazir.
Reish Lakish says that a father may make his son into a Nazir because it is a Mitzvah of Chinuch.
Reish Lakish holds that the Mitzvah of Chinuch applies only to a father not to a mother.
Reish Lakish holds that the Mitzvah of Chinuch applies to a son not a daughter. (1)
Reish Lakish holds that a Hakafah of the entire head is not included in the prohibition of Hakafas Rosh.
Reish Lakish holds that it is not an Isur mid'Oraisa to slaughter Chulin in the Azarah.
Reish Lakish holds that mid'Oraisa a bird may be eaten without Shechitah. (1)
A Chatas ha'Of is brought for a Safek but may not be eaten by the Kohen.
Rebbi holds that a father may make his son into a Nazir until he develops two hairs.
R. Yosi Bar Yehudah holds that he only may make him into a Nazir until he reaches the age of Nedarim. (2)
A BIT MORE
1. However it does require Nechiras ha'Simanim or Akiras ha'Simanim; if the bird dies on its own it is forbidden to be eaten.
2. When a boy reaches the age of 12 years old he has reached the age of Nedarim and any Neder that he makes goes into effect.
MITZVAH OF CHINUCH
Reish Lakish holds that the Mitzvah of Chinuch applies only to a father not to a mother. Tosfos Yeshanim says (Yoma 82) that this is only true regarding the Chinuch for Nezirus, however regarding all other Mitzvos a mother is also obligated to be Mechanech her son. R. Akiva Eiger brings proof to this from the Gemara in Sukah that says that Queen Hilni was Mechanech her sons for the Mitzvah of Sukah.
CHINUCH FOR TEFILIN
A Katan who knows how to guard his Tefilin with Taharah his father must buy Tefilin for him in order to be Mechanech him. (Shulchan Aruch OC 37:2)
If the father did not buy Tefilin for him until he reaches the age of Bar Mitzvah the Mitzvah of Chinuch no longer applies and the child must buy the Tefilin for himself. (Bi'ur Halachah)