I was just doing some research on the net about the Linea nigra, and found this snippet from Wikipedia with another wives tale at the bottom ... interesting..

Linea nigra (Latin for "black line") or linea negra (altered by influence of Spanish negra) is a skin pigment condition during pregnancy where a brownish streak less than a centimeter in width develops. The line runs vertically along the midline of the abdomen from the pubis to the xiphoid process - the bottom-most part of the rib cage in the center or tip of the sternum.

It is caused by pregnancy hormones that increase production of the pigment melanin. This is also known as hyperpigmentation. Fair-skinned women show this symptom less often than women with darker pigmentation. Before it appears it may be more faintly visible as a linea alba ("white line").

Linea nigra tends to appear around the second trimester and may or may not disappear within a few months after birth. Some research suggests there may be a link between linea nigra and insulin. Supplementing the diet with folic acid is said to reduce the discoloration.

There is an old wives' tale associated with linea nigra: if the linea nigra runs to the navel, it's a girl, and if it goes all the way up to the xiphoid, it's a boy.
Mine goes about 2 inches past my belly button - so in the middle!! But I definietly know what we are having!!

Where does yours go to and are you having a boy or girl?