[Magee]

No offence taken, but the simple answer for me is that Commemorative Coins and Stamps are legal tender and accepted everywhere.
I now understand the Birth Certificate must be the Original for government departments thanks to to the replies of members here with more knowledge on this topic than me.
My beef is if the intention of commemorative certificate is only to be a keep sake or to be put on a wall. Then it should have a watermark or be stamped "For display purpose only" or "Not for official use"
The document is issued by BDM and signed by their Registrar. There is nothing to say in it that it cannot be used as an official certificate and since we have lost our son's original years ago we have used this one for schools, sporting clubs and even the police station without anyone ever refusing it.