Scientists and gay rights activists have criticised experiments being conducted in the US that aim to turn gay sheep straight.

Oregon State University is conducting research into the hormonal balance in the brains of rams who are attracted to other rams.

The scientists claim their research is aimed only at reducing or eliminating gay sheep.

About one in ten rams mount other rams instead of ewes. This 10% cost farmers money, and scientists have been experimenting with changing the hormone levels in the brains of these ‘gay’ animals. So far the tests have been successful, with formerly ‘gay’ rams mounting ewes.

The biologist leading the experiments, Charles Roselli, said:

“In general, sexuality has been under-studied because of political concerns. People don’t want science looking into what determines sexuality.

“It’s a touchy issue. In fact, several studies have shown that people who believe homosexuality is biologically based are less homophobic than people who think that this orientation is acquired.”

Roselli also said that possible applications of his research to humans were not a matter for him.

Udo Schuklenk, Professor of Bioethics at Glasgow Caledonian University, who has written to the researchers pressing them to stop, told The Times: “I don’t believe the motives of the study are homophobic, but their work brings the terrible possibility of exploitation by homophobic societies. Imagine this technology in the hands of Iran, for example.

“It is typical of the US to ignore the global context in which this is taking place.”

The relatively simple process of altering the hormonal balance of the brain could easily be applied to humans, raising questions about the nature of homosexuality and the possibility that in future parents could screen unborn children for ‘gayness’ and also have their children treated to become heterosexual.

Critics of the experiments are led by tennis champion Martina Navratilova, who branded them homophobic and cruel, as well as deeply insulting to gay and lesbian people.

She wrote to the university in November, saying, “I respectfully ask that you pull the plug on this appalling and misguided research.

“Surely you can find a way to redirect the millions of public tax dollars that are being wasted on these experiments to a more fruitful venture-perhaps by funding a gay and lesbian community centre to foster dialogue and acceptance for people of all sexual preferences?”

Peter Tatchell, a gay rights campaigner, said: “These experiments echo Nazi research in the early 1940s which aimed at eradicating homosexuality.

“They stink of eugenics. There is a danger that extreme homophobic regimes may try to use these experimental results to change the orientation of gay people.”