daf bit: Nazir 28

[cellio]

The mishna teaches that a man can impose a nazarite vow on his son, but if the son or other relatives object the obligation ends. The gemara justifies this as part of a man's obligation to instruct his son in ritual practices. Reish Lakish asks: how can other relatives interfere in that case? The answer, he says, is that the son can object to any training that is undignified, as shaving the head is assumed to be. (28b-29a)

(The gemara here does not elaborate on how far the "it's undignified" free pass can go. Were I a parent I might find that disturbing. :-) )