A really inconvenient truth. In 2002, thanks to soccer star David Beckham, the world was introduced to the “metrosexual.” Two years later, and with less mainstream-media attention, we got our first exposure to “Intersex.” Intersex is not some new perversion or a weird combination of science fiction and pornography. It is an unfortunate condition that is affecting freshwater fish all over the developed world. It occurs when fish of one sex also exhibit sexual characteristics of the other sex. In 2004, for example, researchers on the Potomac River, downstream from Washington, D.C., found large-mouth bass that in most respects were...