'Gender-Bending' Chemicals Affecting Reproduction in Fish – First Solid Evidence from UK

A four year study, led by scientists from the universities of Exeter and Brunel have discovered that ‘Gender-bending' chemicals which find their way from human products into rivers and oceans have started affecting the reproduction in fishes. The culprit is Endocrine disrupting chemicals (EDCs) coming from sources like female contraceptive drugs, hormone replacement therapy pills and washing up liquid which disrupt the ways that hormones work in the bodies of vertebrates.


The research was done focusing on wild roach in two UK rivers (Bourne and Arun). This is the first solid evidence of EDCs affecting fishes. The scientist discovered 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%. Scientists are apprehensive that some of the effects seen in fish could occur in other animals too as hormone systems are quite similar across all vertebrates.

Catherine A. Harris, Patrick B. Hamilton, Tamsin J. Runnalls, Veronica Vinciotti, Alan Henshaw, Dave Hodgson, Tobias S. Coe, Susan Jobling, Charles R. Tyler, John P. Sumpter. The Consequences of Feminisation in Breeding Groups of Wild Fish. Environmental Health Perspectives.