The contraceptive pill is making fish change from male to female

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Contraceptive pills and chemicals in cleaning products that are flushed down toilets and drains are turning male fish into female fish, new research has shown.

According to the study, the remnants of cleaning products, chemicals and of contraceptive pills have been giving male fish female characteristics.

trout being caught

A new study carried out by leading fish biologist, Professor Charles Tyler from the University of Exeter, has found that one in five male river fish are being affected.

The study found that some male river fish are displaying a reduced sperm quality and some males are even producing eggs.

The chemicals in the contraceptive pill, by-products of cleaning products, plastics and cosmetics, are responsible for this.

“We are showing that some of these chemicals can have much wider health effects on fish we expected,” Said Tyler.

“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 oestrogens found in some plastics affect the valves in the heart.”

According to Tyler 20 percent of freshwater fish at 50 different sites have displayed feminine characteristics and even their offspring are more susceptible to chemical alteration.

Not only are these chemicals giving male fish female characteristics but it is also affecting the fish’s behaviour.

Tyler went on to say that medications such as anti-depressants have made some fish more social, which can be dangerous when it comes to dealing with predators.

Fish are also displaying less aggressive and competitive behaviour making it harder for them to attract females making them less likely to breed successfully.

Tyler’s study also found that over 200 chemicals from sewage plants have been found to have oestrogen-like effects on fish.

“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,” Tyler said.

Tyler will be presenting all of his findings in a keynote lecture at the University of Exeter this week.