Alarm at gender-bending chemicals

The World Health Organisation will urge governments today to establish an immediate inquiry into the effects of gender-bending chemicals on human and animal populations.

Strong evidence links reproductive abnormalities and population declines in some species of birds, fish, reptiles and amphibians with the chemicals, known as hormone disruptors or EDCs (endocrine-disrupting chemicals).

But concerns are also being raised that EDCs have contributed to the increase in breast, testicular and prostate cancers among humans and a decline in sperm counts.

In response to the threat, the WHO will publish a report today, written by a team of scientists, calling for an international programme of research. The report details a large body of evidence pointing to the way wildlife has been harmed by exposure to EDCs, including industrial chemicals such as phthalates, alkylphenols, dioxins and PCBs, as well as herbicides, insecticides and fungicides.

But evidence that human health has been damaged by EDCs remains weak – largely because of the lack of sufficiently robust studies, the report is expected to say.

This means that the effects on adults of low-level exposure to EDCs over a long period of time, and the impact on unborn babies and young children, are poorly understood. But the WHO is expected to conclude that recent health trends are sufficient to warrant concern.

Concerns have been raised about a decline in human sperm quality in several countries, the increased incidence of a congenital malformation of the penis called hypospadias, and a trend towards earlier puberty.

Increases in the incidence of cancer in hormonally sensitive tissues such as the breast, testes and prostate have also led to suggestions that environmental chemicals could be involved. But no studies have established a link. Wildlife studies have, however, shown a link between exposure to hormone disruptors and changes in physiology, sexual behaviour and fertility.

Female fish downstream from pulp and paper mills have developed male sex organs and try to mate with other females.

After a chemical leak in Lake Apoka, Florida, male alligators developed abnormal hormone levels, small penises and feminised gonads that diminished their reproductive success. And fish-eating birds, including gulls and terns, have in the past few decades given birth to an excess of female chicks and chicks with birth defects.