The declension of "ditia" is not very productive (gen "ditiati" etc.) Usually a noun with a rare declension is moved to a different, more conmon declension by a

The declension of "ditia" is not very productive (gen "ditiati" etc.) Usually a noun with a rare declension is moved to a different, more conmon declension by assigning a certain productive suffix which uses a common declension. Such suffixes have their own assigned gender. Same for Russian "rebia" (rare declension) which became rebenok (common declension) by assigning -ok suffix which happens to be masculine. Or in Greek, masculine "pais" had unproductive declension (gen. paidos) so it was assigned diminutive suffux -ion which happens to be neuter, hence modern Greek "paidi" is neuter.