A shocking study reveals that 1/5 of male freshwater fish in Britain are now “transgender” due to chemicals from oral contraceptives and other drugs that are being flushed down household drains. 
Researchers discovered that male river fish are displaying feminized traits and even producing eggs. Reduced sperm quality was observed, along with less aggressive and competitive behavior, making the fish less likely to reproduce successfully.
The findings show that the fish are becoming feminized because of ingredients in birth control pills and by-products of plastics, cosmetics, and cleaning products.
Charles Tyler, a professor at the University of Exeter in the U.K., presented the findings in a symposium keynote lecture the week of July, 2 2017. He explained to the audience that birth control pills are only one cause of transgender or “intersex” characteristics in male river fish. Many other damaging chemicals are discharged by sewage treatment plants.
“We are showing that some of these chemicals can have much wider health effects on fish than we expected.
Using specially created transgenic fish that allow us to see responses to these chemicals in the bodies of fish in real time, for example, we have shown that estrogens found in some plastics affect the valves in the heart.” 
Tests showed that 20% of male freshwater fish, such as roach, at 50 sites had feminine characteristics. Upwards of 200 chemicals from sewage plants have been found to have estrogen-like effects.
Expanding on his earlier statement, Tyler said:
“Other research has shown that many other chemicals that are discharged through sewage treatment works can affect fish, including antidepressant drugs that reduce the natural shyness of some fish species, including the way they react to predators.” 
In the U.S., the Potomac Conservancy in Washington, DC, called for additional research in 2010 after it was discovered that over 80% of male bass fish in the Potomac River displayed female traits, including eggs in their testes. Researchers said the fish’s feminization was likely due to a “toxic stew” of chemicals. 
 The Telegraph