Omphalophobia is the fear of bellybuttons, and particularly of having one's bellybutton touched, or sometimes of seeing one being touched. It is sometimes linked to the feeling of an umbilical cord still being linked to the internal organs. Some sufferers may become nauseated from just a picture of a navel. As for most phobias extensive therapy or medication can be effective at relieving the anxiety that comes with the phobia.
The term omphalophobia comes from the Greek ὀμφαλός - omphalos, meaning "navel" and φόβος - phobos, "fear".)