SCIENTISTS IN CHINA say they had found that a group of mice, bred with brains which are unreceptive to a common hormone, have lost the impulse to mate with females – and turned them homosexual.

The research, published in the journal ‘Nature’, claims that the mice – which were specially bred not to produce serotonin, known as the ‘happy hormone’ – lose the preference for mating with females displayed by the unmodified mice.

When presented with a choice of either male or female, the mice showed no preference for either gender – but when only a male was introduced to the cage, the modified breed were far more likely to issue the so-called “mating call” and attempt to mate with the new male introduced.

When the experiment was then repeated with a different set of mice – who were bred without a gene needed to produce serotonin – the same results were observed, BBC News reported.

But when serotonin was then artificially introduced back into the brains of the specially bred mice, their preference for mating with a female was “restored”.

“This is the first time, to our knowledge, that a neurotransmitter in the brain has been demonstrated to be important in mammalian sexual preference,” the report declared.

Its authors said, however, that it would be dangerous to draw similar conclusions about the nature of human sexuality from the results.