The Environment Agency study looked at the health of more than 1600 roach found in 51 rivers and streams around the country.
Overall, a third of the male fish were between sexes. However, in one waterway, near a particularly heavy discharge of treated sewage more than 80 per cent had female characteristics.
Tests showed the males developed female sex organs and were producing eggs. Such fish also produce less sperm and the sperm that is produced is of low quality. Females may also be affected, producing abnormal eggs.
Previous studies have that cod, trout and flounders are all being feminised.
Evolutionarily, this could be disastrous for the English human population as well, as this is slipping into the English drinking water:
Although there is no conclusive proof, it is thought the hormone, which has similar actions in fish and humans, could be partly to blame for falling sperm counts in men.
British men's sperm counts dropped by almost a third between 1989 and 2002, and one in six couples now have difficulty conceiving.