Uuummm.....has anyone ever seen the movie Jurassic Park?
I know there is a difference between fact and fiction, but often times Facts are stranger than Fiction.
There are apparently animals that do change genders to keep reproduction at optimal levels. I have read multiple articles on the subject. Just found a quick one off the web, not sure if the source is reliable.
http://www.myoc.com/community/enviro...heephead.shtml