FEARS that "gender-bender" chemicals could find their way into the region's drinking water were played down by the Environment Agency yesterday.

The waterways watchdog has confirmed it has commissioned a report, to be published later this month, which indicates that levels of oestrogen in some rivers in the UK is worryingly high.

It found male fish with both male and female reproductive systems in several rivers, including the Ouse in North Yorkshire and the Aire and Calder, in West Yorkshire.

The hormone, originating from urine from women using the contraceptive pill, the chemical is thought to survive water treatment works and making its way into rivers, altering the sexuality of fish.

There were claims on the BBC's Countryfile programme yesterday that the Environment Agency is on the point of demanding a massive investment by the water industry to ensure drinking water supplies are not affected by oestrogen.

However, an agency spokeswoman said last night there was no evidence to suggest drinking water had been affected.

"This is nothing new; in fact, research into the issue began two years ago and there have already been some improvements since," she said. "Oestrogen has been detected in our rivers and it has clearly had an impact on fish populations - but there is no evidence of any impact on the drinking water supply.

"Nevertheless, the impact oestrogen is having on fish stocks needs to be studied more closely and the Environment Agency needs to work with the water industry and other partners to see if there is anything we can do to improve the position," she said.

A spokesman for Yorkshire Water said: "We have very advanced processes at all our water works to protect the drinking water system.".

"However, that aside, there is evidence to suggest oestrogen is having an impact on our rivers and that is an issue the whole industry needs to look at in more detail."