A taxon is a conventional name biologists use to refer to a particular group of species, being a class, a family, or any other. In this case, we have to consider class is a bigger group than family, in fact, a class is conformed by multiple biological families. For instance, we have the class Mammalia, where we can find the order Primates, and at the same time in Primates, the family Hominidae, where are we, the human species; Homo sapiens. So the taxon that includes more genera is class, instead of family, since class includes many biological families in, and in consequence, much more taxonomic genera.