For a single generation it is not a problem but what happens if this catches on and everybody changes or alters their surname every generation? .......... msnimje
In the Spanish system that voiceinthewind mentions, the surname is not "changed" with every generation. The surnames are merely expressed in combination in more formal situations such as when someone maybe called "Mary" or "Mary Ellen".
The "hyphenated surname" currently in vogue in the U.S. destroys both surnames and is a genealogical abomination. As msnimje, points out, it becomes unworkable after John Smith-Brown marries Joan Wilson-Parker and have a child named Tom Smith-Brown-Wilson-Parker who will later marry Karen Kowalski-Jacobs-O'Brain-Kelly who will produce John Smith-Brown-Wilson-Parker-Kowalski-Jacobs-O'Brain-Kelly.
The Spanish "first and second surnames used in more formal situations" system that voiceinthewind is talking about simply keeps the maternal Grandpa from being totally ignored, brings order into the chaos of a genealogy of multiple generations of Smiths each married to a Mrs. Smith and begetting more Smiths who marry other Mrs. Smiths, and, even 300 years later, keeps maternal Grandpa's surname in the picture.
By contrast, as I pointed out in Post 93, in the U.S. system, even the father of such a famous person as First Lady Laura Bush is as invisible as a Stealth fighter by the time his grandchildren are born.
In the Spanish system, the individuals in the marriages listed before would be referred to as follows:
In less formal situations, the father, son and grandon would be introduced as:
John Smith
Tom Smith
John Smith
In more formal situations and in official records, the father, son and grandon would be introduced and listed as:
John Smith Brown
Tom Smith Wilson
John Smith Kowalski
In the Bush geanealogy, in more formal situations, the father, son and granddaughter would be introduced and listed as:
George Bush Walker
George Bush Pierce
Jenna Bush Welch
The maternal surname therefore becomes a "tag" after the paternal surname such as Sr. or Jr. or III. In the Spanish system, there is no need to differente between five different "John Smiths" as each "John Smith" has his own different maternal surname tag. Therefore, in Spain, only Kings and Queens have Roman numerals after their names.
As you can see, the Spanish system keeps the surnames of the fathers of these two women in the public eye:
See my Post 93.
In my own genealogy, the Spanish system has been a fantastic help in documenting maternal lines from hundreds of years ago and determining where persons with the same first name and paternal surname fit into the genealogical tree.
Given the choice between passing on their surnames to their wives at the expense of their fathers-in-law and the choice of passing on their surnames to their daughters and their grandchildren in their daughters' families for centuries to come, the Spaniard chooses the latter option.
I once read about an American couple who lived in Spain for a few years and shared the same surname as in John and Mary Smith. Their neighbors kept telling the husband what a nice sister he had. :-)