Both the bride and groom have to declare at the wedding which name they will use, and they have to declare which family name their children will get (which can be changed until the birth of the first child). Children can get either parent's surname, if it is on the marriage certificate, but all children must have the same surname. Since 2004 they can also get a hyphenated name, but only if both parents kept their birth names at least as one part of their new name. Children usually get their father's surname, but hyphenated names are becoming more common.