Genethliac :: Genethliac (a.) Pertaining to nativities; calculated by astrologers; showing position of stars at one's birth.
Genethliacs :: Genethliacs (n.) The science of calculating nativities, or predicting the future events of life from the stars which preside at birth..
Genethlialogy :: Genethlialogy (n.) Divination as to the destinies of one newly born; the act or art of casting nativities; astrology.