Welsh scientists have used sticklebacks to answer an age-old question - what makes some males more attractive?
Sticklebacks suffocated after a stretch of water was polluted
Researchers from Cardiff University identified a chemical that makes male fish smell more appealing.
In a three-year project, they found certain males produced small protein fragments, called peptides, and used them to produce a synthetic scent.
It is a powerful attractor for female sticklebacks and the team says similar "fragrances" could be made for humans.
But men hoping the discovery might be the answer to their prayers will be disappointed.
Each artificial scent would have to be tailor-made to suit the individual, so the cost would be beyond the reach of most ordinary people.
"Theoretically, it is possible," said Dr Griffiths from the Cardiff School of Biosciences. "But it is unlikely to be very practical, because you would have to devise a perfume for every individual person - and that would be very expensive indeed."
The research on hundreds of small fish was carried out by a Welsh-German team. They already knew that female sticklebacks were attracted to males that had immunity to certain parasites and illnesses, so that their offspring would have the best chance of survival.
Dr Griffiths, a behavioural ecologist, explained that sticklebacks were chosen for the project because of their size and because a lot was already known about their biology.
All creatures with backbones - whether fish or humans - have the same kind of immune systems, so the results of the Cardiff study can be widely applied.
Experimenting on humans would have been difficult
"Sticklebacks are small and easy to handle, and they are a darn sight easier to work with than humans," Dr Griffiths added.
"We can get female students to sniff the armpits of male students, but we cannot get them to go as far as choosing a husband and starting a family.
"But with the fish, we were able to follow the experiment through to the end, which was spawning.
"Basically, a female with a natural immunity to A and B would look for a mate with immunity to C and D. She looks for the immunity she needs for the benefit of her offspring.
"Humans have used perfumes for thousands of years. Perhaps these results explain why some perfumes smell good on some people and terrible on others."
In the tests conducted, even males previously rejected by female fish were made irresistible when the synthetic perfume had been applied.