Professor Charles Tyler, reproductive physiologist and environmental biologist at the University of Exeter (United Kingdom), has found that chemicals from contraceptive pills and other household cleaning products are causing fresh-water male fish to develop female parts and even to lay eggs.
Tyler’s research has shown that oestrogen and other chemicals being washed down the drain are causing male fish to reduce “sperm quality and display less aggressive and competitive behaviour, usually associated with attracting females of the species, which make them less likely to breed successfully,” reported Exeter in a press release.
Tyler presented his research on July 3 in a keynote address at 50th Anniversary Symposium of the Fisheries Society in the British Isles, held at Exeter University. His lecture was titled “The Feminisation of Nature – an Unnatural History.”
In the lecture, he laid out data on the Roach fish in particular, and how estrogens are causing some males to develop ovaries and become an “intersex.”
One of Tyler’s research reports (which he sighted in his presentation) explained that “intersex” fish are male fish that “can have feminized reproductive ducts and/or developing oocytes within their testes (Nolan et al. 2001). They also “have abnormal concentrations of sex steroid hormones (Jobling et al. 2002a) and (often) elevated concentrations of the estrogen-dependent blood protein vitellogenin (VTG) in their blood (Jobling et al. 1998).”
This research also states that “fertility is reduced” in feminized fish.
“We are showing that some of these chemicals can have much wider health effects on fish that 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 oestrogens found in some plastics affect the valves in the heart, “ Tyler said in the Exeter press release.
He added, “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.”
When CNSNews.com asked Tyler how long he has been doing research on transgender fish, Tyler responded in an email, “I have been working on sexual disruption in fish as a consequence of exposure to chemicals for years.”
Tyler also corrected the word “transgender” with regard to the fish, saying, “I think it may be better to call them intersex fish -- as some people like to use the term transgender in the human context only.”
In his presentation, Tyler also mentioned that chemicals are having this effect on fish in other continents around the world: “Feminised Fish have been reported from sites across Europe, America, Canada ( Rainbow Darter - Etheostoma caeruleum, Percidae), Africa and Asia.”
On this topic, CNSNews asked Tyler, “Slide 15 mentions that fish are being ‘feminized’ in other continents around the globe. Is this a result of contraceptive chemicals as well? Or is it something else?”
Tyler responded, “The feminising effects on fish in other countries does indeed include effects from the contraceptive pill, but also from chemicals including industrial surfactants - detergents, plasticisers and bulk chemicals such as bisphenol A.”
He further stated in his presentation that human males are experiencing “falling sperm counts.”
When CNSNews.com asked Tyler whether this was from chemicals in contraceptives or if it was from something else, the professor answered, “Falling sperm counts likely has a complex aetiology. This will not be due to the contraceptive oestrogen, but more due to other chemicals that we consume in our diet. These chemicals include bisphenol and phthalates -plasticisers.”