Free Stripping Down Science by Chris Smith, Dr Christorpher Smith Page A

due to an overall difference in attractiveness. Instead, the results suggest that men can subconsciously detect when women are at their most fertile and judge them to be more attractive, valuable and, it would seem, worthy of more attention and larger tips at this time. As Miller points out, ‘This is the first time that anyone has shown direct economic evidence for the existence and importance of oestrus in human females.’
    It’s not known what triggers the effect. It could be down to altered behaviour on the part of the fertile woman, such as chatting engagingly or wearing more provocative clothing and make-up, or it might be that chemical cues, like pheromones, are responsible. A strong possibility is that the sound of the woman’s voice plays a part too. Indeed, the appropriately named Nathan Pipitoneand his colleague Gordon Gallup, two researchers from the State University of New York at Albany, 32 have recently discovered that the menstrual cycle affects how attractive a woman sounds.
    Evidence for this fertile form of conversation emerged when the scientists made recordings every week for one month of the voices of 30 female students counting to 10. About half of the students they studied were contraceptive pill users, the other half reported regular, natural menstrual cycles. The four recordings from each of the women were played back, in a random order, to a large panel of ‘raters’ consisting of equal numbers of male and female students who were asked to judge the attractiveness of the voices they were hearing.
    When Pipitone and Gallup matched up the scores given to each woman with where she was in her menstrual cycle when each of the recordings was made, a pattern just like the lap dancers’ tips emerged. The voices of non-pill-using females were rated as significantly more attractive at the times when the women were ovulating, and therefore most fertile, compared with other timesof the month. Amongst the pill users, on the other hand, the voice ratings barely changed across the month. There were also no differences between the verdicts of the male and female raters.
    So how does this happen? It’s probably down to the levels of the sex hormones oestrogen and progesterone. Scientists have found that lower levels of oestrogen and higher levels of progesterone, which occur towards the end of each monthly cycle, can cause the vocal cords to swell slightly, reducing voice pitch. And as lower-pitched voices, studies have shown, tend to be rated as less attractive than higher voices, this could explain the effect.
    Regardless of how women broadcast their fertility – and researchers suspect that a combination of different signals is involved as a form of ‘multiple messaging’ – the effect does appear to be real. The bottom line would seem to be, ladies, if you want that new car at a knockdown price, consider ditching the pill, time your approach to coincide with day 14 and always head for the male sales assistant …

It’s well known that women can influence each other’s menstrual cycles using just the power of smell: ladies living together can synchronise their periods and, experimentally, women sniffing pads worn in the underarms of other females can alter their menstrual timings by up to two weeks. But if you still thought men were immune to the effect, then you’ve been myth-led – because males too, it now turns out, are equally sensitive to ladies’ smells. In fact, research has shown that men exposed to the whiff of a woman experience a testosterone surge, although only on certain days of the month.
    This came to light recently when two scientists at Florida State University, Saul Miller and Jon Maner, 33 asked a group of 37 heterosexual (and possibly ‘metrosexual’) young men to lend their noses in the name of science and sniff some ladies’t-shirts. The men, who did not know the purpose of the study, were asked to smell