Next time you’re tempted to join a sexy woman on the dance floor, consider this — she might be very fertile. New research shows that men are fertility detectors, picking up signals that women give out when they move.

According to an article on LiveScience, men unknowingly deemed women who were in the fertile stage of their menstrual cycle as more attractive on the dance floor than women in the non-fertile stage.

The study published in the journal Personality and Individual Differences, filmed the silhouettes of 48 women aged between 19 and 33 dancing to an identical drumbeat from a Robbie Williams song during the fertile phase of their menstrual cycle and again during their nonfertile phase.

The researchers determined the women's fertility by counting back from the women's previous period.

The silhouettes of the women dancing were shown to 200 male under-graduate and graduate students who were asked to rate the dancing women's attractiveness on a seven-point scale. The women all wore identical body-fit clothing and their hair was pulled back and out of their faces – to diminish any differences.

The researchers from the University of Göttingen in Germany said the fertile women were given an average rating of 2.88 while dancing in the video clips and 3.31 while walking. The nonfertile women were given an average rating of 2.72 while dancing and 2.98 while walking.

The men had no knowledge that women's fertility was being analysed.

According to the researchers, the findings seem to imply that ovulation is not as secret as we might have previously thought.

"These changes are subtle, and women may not always be consciously aware of them. However, men seem to derive information on women's fertility status from these cues," study researcher Bernhard Fink was quoted as saying.

Previous studies have suggested that a woman's behaviour changes slightly when she is fertile. She is said to desire strong-jawed men more and to have an increase in sexual desire. Other studies also seem to indicate that men seem to prefer the facial attractiveness, smell and voice of fertile women as opposed to nonfertile women.

Interestingly, a famous 2007 study from the University of New Mexico showed that exotic dancers earned more money when they were fertile.

According to the study which was published in the journal Evolution and Human Behaviour, the dancers were in close contact with their clients so therefore their enhanced attraction while fertile could possibly be pinned down to a range of factors, such as smell and movement.

They suspect that their oestrogen levels (which is said to affect ligaments, muscles and tendon strength) are in flux causing women to move differently.