Why Boys are Turning into Girls: 'Gender-bending' Chemicals Affect Reproduction

Research Proves 'Gender-bending' Chemicals Affect Reproduction

October 26, 2010

University of Exeter - New research has provided the first evidence that 'gender bending' chemicals which find their way from human products into rivers and oceans can have a significant impact on the ability of fish to breed in UK Rivers.

The findings from the four year study, led by the universities of Exeter and Brunel, has important implications for understanding the impacts of these chemicals on ecosystem health and possibly on humans.

Endocrine disrupting chemicals (EDCs) disrupt the ways that hormones work in the bodies of vertebrates (animals with backbones), including humans.

They can be found in everything from female contraceptive drugs and hormone replacement therapy pills, to washing up liquid, with the most well studied EDCs being those that mimic oestrogen (female hormone).

EDCs have been seeping into rivers through the sewage system for decades and have an observed effect on fish, altering male biology to make them more female – hence the 'gender bending' reputation of these chemicals.

Until now, there has been no solid evidence to show the long-term impact of this effect on fish in the wild - but the new research focusing on wild roach in two UK rivers (Bourne and Arun) has provided new evidence.

Two large-scale breeding studies assessed the ability of fish to breed by using a genetic technique (DNA microsatellites) to match offspring produced to their parents.

It was found that intersex fish – those that had their sexuality compromised by EDCs and which contain both male (sperm) and female (eggs) sex cells – had their reproductive performance reduced by up to 76%.

Charles Tyler, from the University of Exeter's Biosciences department, jointly led the research alongside Professor John Sumpter, from the Institute of Environment at Brunel University. Prof Tyler said:

"This is the first time we've seen firm evidence that the intersex fish, males that have been feminised by EDCs, have a reduced ability to breed.

"Clearly this raises concerns about the implications on the future for wild fish populations living in UK rivers, but there's also much wider issues raised by these findings. Some of the effects seen in fish could occur in other animals too as hormone systems are quite similar across all vertebrates.

"EDCs have been tentatively linked with human health impacts too, including, falling sperm counts and cardio-vascular disease. These findings remain more controversial," Prof Tyler added. "In contrast, we have shown, unequivocally that environmental oestrogens alter sexual development in fish and now, through this study, that this can impact on their ability to breed".

Fish are seen as a key indicator of the impacts of chemicals such as EDCs because they soak them up in far larger quantities than humans ever would, concentrating any potential side-effects.

Their biology also means they are particularly prone to the feminising effects of EDCs because their sex is not decided until after birth – meaning they are more susceptible to outside influence.

Prof Tyler concluded:

"Fish still share many biological links with humans and the fact that their reproduction has the potential to be affected by EDCs is certainly a cause for concern. From a risk assessment point of view, these results are very significant."

More information: The full paper, called Consequences of Femininisation in Breeding Groups of Wild Fish, is published in Environmental Health Perspectives online and can be viewed here.

Bisphenol-A now linked to male infertility
The problem with phthalates and link to sexual development (Reuters, October 18, 2010)
The global chemicals industry produces nearly six million tonnes of phthalates every year. Some scientists, and an increasing number of governments, have begun to suspect that phthalates might be connected to a massive drop in male fertility globally over the past few decades -- in the developed world, repeated studies have shown sperm counts have decreased by about 50 percent in the past half century -- as well as to problems with the sexual development of boys in the womb.

Why Boys are Turning into Girls

Gender-bending chemicals are largely exempt from new EU regulations, warns Geoffrey Lean.

October 23, 2009

London Telegraph - Here's something rather rotten from the State of Denmark. Its government yesterday unveiled official research showing that two-year-old children are at risk from a bewildering array of gender-bending chemicals in such everyday items as waterproof clothes, rubber boots, bed linen, food, nappies, sunscreen lotion and moisturising cream.

The 326-page report, published by the environment protection agency, is the latest piece in an increasingly alarming jigsaw. A picture is emerging of ubiquitous chemical contamination driving down sperm counts and feminising male children all over the developed world. And anti-pollution measures and regulations are falling far short of getting to grips with it.

Sperm counts are falling so fast that young men are less fertile than their fathers and produce only a third as much, proportionately, as hamsters. And gender-bending chemicals are increasingly being blamed for the mystery of the "lost boys": babies who should normally be male who have been born as girls instead.

The Danish government set out to find out how much contamination from gender-bending chemicals a two-year-old child was exposed to every day. It concluded that a child could be "at critical risk" from just a few exposures to high levels of the substances, such as from rubber clogs, and imperilled by the amount it absorbed from sources ranging from food to sunscreens.

The results build on earlier studies showing that British children have higher levels of gender-bending chemicals in their blood than their parents or grandparents. Indeed WWF (formerly the World Wildlife Fund), which commissioned the older research, warned that the chemicals were so widespread that "there is very little, if anything, individuals can do to prevent contamination of themselves and their families." Prominent among them are dioxins, PVC, flame retardants, phthalates (extensively used to soften plastics) and the now largely banned PCBs, one and a half million tons of which were used in countless products from paints to electrical equipment.

Young boys, like those in the Danish study, could end up producing less sperm and developing feminised behaviour. Research at Rotterdam's Erasmus University found that boys whose mothers were exposed to PCBs and dioxins were more likely to play with dolls and tea sets and dress up in female clothes.

And it is in the womb that babies are most vulnerable; a study of umbilical cords from British mothers found that every one contained hazardous chemicals. Scientists at the University of Rochester in New York discovered that boys born to women exposed to phthalates had smaller penises and other feminisation of the genitals.

The contamination may also offer a clue to a mysterious shift in the sex of babies. Normally 106 boys are born for every 100 girls: it is thought to be nature's way of making up for the fact that men were more likely to be killed hunting or in conflict. But the proportion of females is rising, so much so that some 250,000 babies who statistically should have been boys have ended up as girls in Japan and the United States alone. In Britain, the discrepancy amounts to thousands of babies a year.

A Canadian Indian community living on ancestral lands at the eastern tip of Lake Huron, hemmed in by one of the biggest agglomerations of chemical factories on earth, gives birth to twice as many girls as boys. It's the same around Seveso in Italy, contaminated with dioxins from a notorious accident in the 1970s, and among Russian pesticide workers. And there's more evidence from places as far apart as Israel and Taiwan, Brazil and the Arctic.

Yet gender-benders are largely exempt from new EU regulations controlling hazardous chemicals. Britain, then under Tony Blair's premiership, was largely responsible for this – restricting their inclusion in the first draft of the legislation, and then causing even what was included to be watered down.Confidential documents show that it did so after pressure from George W Bush's administration, which protested that US exports "could be impacted".

Now the Danish government is planning to lobby to have the rules toughened up. It is particularly concerned by other studies which show that gender-bending chemicals acting together have far worse effects than the expected sum of their individual impacts. It wants this to be reflected in the regulations, citing its discovery of the many sources to which the two-year-olds are exposed – modern slings and arrows, as it were, of outrageous fortune.

Phthalate warning: Medications contain chemicals that “feminize” unborn baby boys