My children were given hyphenated last names as well, but for a much different reason. In Mexico, they would have received my maiden name as a surname following the father's surname. Since the children were born and certified in the US, we hyphenated the names as they would have been given in Spanish.(only ten letters in all) Without the hyphen, their US surname would have been my maiden name. ie Zoe T. SmithJones as opposed to Zoe T. Smith-Jones. Friends of mine that moved to the US from Mexico ended up with his mother's maiden name as surname when some bureaucrat decided he/she knew better than they did what their surname is.