The Ankh was the Kemetic symbol for life, also know as the handled cross.  It represented the unification of the feminine and masculine forces of the universe and creation of new life.  It portrayed both the spiritual and physical aspects of life.  The phallus represents the male and the circle on the top represents the female yoni or origin of life. 

I wear an ankh as a symbol of the male/female connection and the origin of life.