Women find the scent of other women most attractive when they are at their most fertile, scientists have found.
It has long been known that men find the natural scent of women more attractive at times when they are most likely to conceive a baby.
But from an evolutionary point of view, the fact women find the smell of potential rivals pleasing is harder to explain.
Researchers from Chapman University in California asked women to rate sample smells presented to them in terms of sexiness and intensity.
The authors, led by Kelly Gildersleeve, wrote: ‘Like men, women rated naturally-cycling women’s high-fertility scent samples than their low-fertility samples.’
The women whose scents were used were not wearing perfume or anti-perspirant.
In all, 21 naturally-cycling women and 12 women taking the pill participated as scent donors. A total of 96 women aged between 18 and 40 were asked to rate scents in two ways. One involved choosing between two scents from the same woman – when at her most fertile and at her least fertile.
They were also asked to rate individual scents in terms of pleasantness, sexiness and intensity, between one and nine.
Forty-eight of the ‘testers’ were heterosexual, 22 were gay and 16 bisexual.
The authors concluded: ‘The findings indicate that, like men, women perceive cues of high fertility in other women as attractive. Specifically, women rated other women’s high-fertility natural body scents as more pleasant, sexier, and perhaps less intense than their low-fertility scents.’
Possible explanations for the phenomenon are that the ability to detect differences in another female’s fertility is a vestige of an ability that evolved in an animal ancestor. Alternatively it could be that the feature works in women ‘as a mere byproduct of their shared physiology with men’.
But the researchers think it must have given women an advantage in the past for it to have continued in women today.