There are two elements to a ketuba. One is that it is a binding monetary document that obligates the husband or his inheritors monetarily to the wife. Additionally, there is a religious requirement for the woman to possess a valid ketuba; without it, the couple is forbidden to live together.[3] The reason for the latter rule is that a woman must have at least a minimum feeling of security that her husband cannot divorce her without a reasonable monetary consequence.[4] Thus, it is critical for her to be confident that she has a valid ketuba. (There is a basis to say that if the wife believes that the ketuba is valid, even when it has a mistake that invalidates it, they are permitted to live together if she is unaware of the mistake.[5] There are other elements of leniency to consider to allow their living together without a valid ketuba document,[6] but these have problems and are beyond our present scope.)
The two elements of the ketuba are connected. If it can be used as a valid legal document, it also serves the religious function. Although we try to make the ketuba as complete as possible, and some invoke some of the stringencies of a get document, the basic requirement is that the ketuba can stand up to a review in beit din.
Does the mistake that you raise invalidate a ketuba, or some other document for that matter? There is a rule regarding documents that distinguishes between different types of mistakes. A ta’ut d’muchach (when it is clear from the context what was intended to have been written, despite the mistake) does not invalidate a document.[7] The writing of “son of” instead of “daughter of” in the place of the ketuba that relates to the bride is possibly one of the clearest examples of a ta’ut d’muchach. In addition, since the name of the bride, including her father’s name, appears correctly elsewhere in the ketuba, there is even more reason to ignore the mistake, as this shows clearly that the mistake is a ta’ut d’muchach and how the name should have been written.[8]
The Itur[9] does maintain that a minor mistake in the names in a document should be corrected. However, it appears that the motivation for this is that a name could be anything and it is hard to know what was intended. However, although the word “ben” or “bat” could be confused in a regular document because of the possibility of a unisex name, this does not apply to a ketuba, where there is a distinct place for the name of the groom and for the bride, respectively. Furthermore, the Rosh[10] confirms the validity of the document in a case of a clear mistake regarding names. Therefore, the ketuba is valid, and the couple can continue to live together with the ketuba as is.
Usually, there are ways of fixing mistakes (this is too detailed to discuss here), but they become more complicated the later in the process they are discovered. The mesader kiddushin, who apparently made the mistake (as he is human), can be contacted regarding the proper steps to take. There is a possibility of replacing the ketuba with a new one. However, in general, replacement ketubot have altered texts, at least when signed on a later date than the first one.[11] These changes make things more complicated and, in addition, will look strange to those who read the new ketuba’s content. Your friends and the mesader kiddushin can discuss what to choose from among the different options. However, the couple has the halachic right to decide to leave things as they are.