Dieezah Aug 4, 2011:

@polyglot45 Cela fait un peu bizarre, surtout pour un document légal... De plus ce n'est pas suffisamment explicite...
@Izzy," les parents" will look weird on an official letter... It will be acceptable and understandable enough in informal conversations but that's all... You could choose to split one of the couples to makes things clearer... Like this :
Monsieur et Madame Smith (these are the parents obviously)
Monsieur Smith, fils et son épouse...
That would make things clear enough and it is perfectly correct written French...
You could do it the other way around too, Monsieur Smith père et son épouse..;.

polyglot45 Aug 4, 2011:

et si on disait l'aîné des M. Smith et son épouse ?