What if it could release a chemical that would make an opposing army's soldiers think more about the physical attributes of their comrades in arms than the threat posed by the enemy? And thus the "gay bomb" was born. Far from being the product of conspiracy theorists, documents released to a biological weapons watchdog in Austin, Texas confirm that the US military did investigate the idea. It was included in a CD-Rom produced by the US military in 2000 and submitted to the National Academy of Sciences in 2002. The documents show that $7.5m was requested to develop the weapon.

The documents released to the Sunshine Project under a freedom of information request titled "Harassing, Annoying and Bad Guy Identifying Chemicals" includes several proposals for the military use of chemicals that could be sprayed on to enemy positions. "One distasteful but non-lethal example would be strong aphrodisiacs, especially if the chemical also caused homosexual behaviour," says the proposal from the Air Force's Wright Laboratory in Dayton, Ohio.

The Pentagon did not deny that the proposal had been made: "The department of defence is committed to identifying, researching and developing non-lethal weapons that will support our men and women in uniform."

Aaron Belkin, director of the University of California's Michael Palm Centre, which studies the issue of gays in the military, said: "The idea that you could submit someone to some aerosol spray and change their sexual behaviour is ludicrous."