Btw, I’m an Australian, a member of the British Commonwealth, and I can honestly tell you, that in all of my long life, I have never met a Jr.
A boy might be referred to as junior if he has the same name as his father, but on a birth certificate, as part of his name?
Never.
Neither have I run across a II or what-ever as part of a name. But in english lit and history, it’s quite common.
That’s odd that you’ve never met a Junior. Not even one? For some reason it’s not a popular custom in Australia? It’s definitely not a custom in Jewish families.
I know many with a suffix. Whether it’s on their birth certificate, I have no idea, but it’s on at least one of their passports. I’ve knowns Jr, II (named after a grandfather), III, IV and V’s. One V was called Quint because of his V.