It has been known for many years that the menstrual cycles of women who live together do not come into synchrony. It’s merely an artefact of random fluctuations and differences in cycle length that give the appearance of some kind of synchrony when co-habiting women find that they seem to be having their period at the same time. (Remember, if you’ve noticed this in a shared house, anecdote is not evidence). Studies do not support the idea and show that it doesn’t happen, despite what you want to believe.
It was surprising then to read the phrase “menstrual synchrony” in the context of a press release about a recent research paper into the apparent fluidity of female sexuality, discussed as it if were a fact rather than deceived wisdom. Doesn’t fill you with confidence regarding any of the other assertions being made, I must say.
Strassman had doubts in 1998 and Yang and Schank put paid to the idea in 2006 in Human Nature. And, curiously, this same topic was debunked recently by Tom Chivers in The Spectator.
I did a quick search for the phrase “menstrual synchrony” there seem to be as many people claiming that it is real as there are people pointing to the actual scientific evidence that shows that it’s not and a similar number of obnoxious men talking about how their afternoon bowel movements seem to be in synchrony with their male work colleagues…