The enormous difference between male and female sexual behaviour may be explained, in animals at least, by a tiny organ in the nose rather than by any gender difference in brain circuitry. So say investigators in the United States, who admit to being stunned by the finding and the implications for the understanding of sexuality. In a study published by the British journal Nature, the team engineered female lab mice so that the rodents lacked a gene called TRPC2, effectively short-circuiting the so-called vomeroasal organ. This tiny organ in the nose is packed with receptor cells that pick up pheromones ? primitive cents that trigger aggression and sexual response in land-dweling vertebrates.

To the scientists? surprise, the mutant female mice behaved like men at a Seventies disco night. They sniffed and ran after females, flounced their pelvises, mounted and thrust at male mice, issuing ultrasonic queaks of the kind that males emit to show lurve.