Tim Harford and the More or Less team try to make sense of the statistics which surround us. From BBC Radio 4
http://www.bbc.co.uk/programmes/p02nrss1
WS More or Less: Menstrual Syncing
It is a commonly held belief that if women spend enough time together, their bodies start to communicate through chemical signals, known as pheromones. Eventually the women’s bodies will start to menstruate at the same time. But where does this idea come from? And is it really true? We look at the evidence and wonder – could it be down to chance?