Are boys not supposed to know about their sister's getting their periods? Is puberty a dirty secret in most households?

A top rated post in another sub really confused me and I would like some answers because a dad was essentially told he was wrong for telling his son that his twin sister got her period.I have 4 kids. Two boys (13 years old and 3 years old) and two girls (15 years old and 15 months old). Because of the mixed genders puberty has never been a huge secret. We told the kids about puberty for both genders so they could be sensitive to what their siblings are going through. When my daughter started her period we told her brother because they share a bathroom and didn't want him to be grossed out by pads in the bathroom garbage if it was his turn to take it out. It was never a big deal and I imagine we will do the same when the little ones get older.Is this weird? via /r/Parenting https://ift.tt/2OhpWX4