Vous etes Francaise, n'est pas? Its surprising you got away with an kreative name, because I know the French authorities are very strict et pas du tout laisser-faire avec such names. I remember reading about the French government sueing a couple called Renault because they wanted to call their daughter Megane, so as to protect them from the future jeers of her froggy classmates(for those who are not familiar, Renault Megane is a popular french car).
All I can say about Thewis is that according to the Anagram Oracle, you must spend a
FORTUNE on pampers, 'cause two anagrams of Thewis are "His wet!" and "We sh*t" :P