3.1 Gender change. In the languages that distinguish names by the gender of the person possessing them, the possiblity that a single spelling can come to refer to a person of either gender, or to someone of the other gender must be considered. In some languages there are two forms of a surname, one for each gender. For example, in Roman times if the husband were named Appius Claudius, his wife might be, Anna Claudia.
Given names in English have characteristic suffixes and other formal adjustments that will change the masculine form into a feminine one. The one example I have found of a feminine name being transformed into a masculine one has a parallel change going the other direction, so that analogical force may be appealed to as a possible factor in its unusual stability.
In German there is a suffix added to a surname to indicate for women their maiden name. Thus the suffix {in} indicates marital status as well as gender. Sometimes this suffix is not easy to distinguish. When a surname already ends in in, that fact may not be evident until one notices an extra in in the womans version. When a surname is inherently weak, ending in an e, this vowel is dropped before adding the in ending. The researcher might think the surname to be strong (not ending in an e), until it is observed that the surname sometimes occurs without the ending.
In some cultures there is a family name in the form of a patronymic that belongs to each of the children in a family. Usually the patronymic contains information in its form about the gender of the person who carries it as a surname.