A little stickleback fish (Gasterosteus aculeatus) nicknamed "Mary" appears to have leaped across a major reproductive divide on the evolutionary tree of life. Stickleback females, like most female ...

Male freshwater fish are taking on transgender form and developing female characteristics -- including the ability to produce eggs -- in what researchers are linking to exposure to birth control pills ...

Add Yahoo as a preferred source to see more of our stories on Google. The fish swimming in the streams, rivers, and lakes around your town are probably on Prozac. Now new research from the U.S.