As I was driving to work today, I was following a vehicle with a "Darwin fish" on the back - if you haven't seen them, visit evolvefish.com and you'll quickly realize what I'm talking about. The "fish" reminded me (as it should) of the Christian hijacked vulva symbol.
As with most of Christianity, the fish symbol was taken from earlier pagan religions. The fish represented the Great Mother Goddess - her vulva to be exact. The fish symbol was later adopted by Christianity with a number of myths created to have it fit - only the genital meanings were abandoned.
Enjoy your "true religion" while I enjoy giggling at the vulva on your car.