According to the journal, Biological Reviews, evolution likely has a hand in the reason women can apparently “change their s#xual desires and identities from lesbian, to bis#xual, to heteros#xual and back again.” The lead author of the study, Dr. Satoshi Kanazawa, suggests, the evolutionary pressures of polygamy may have influenced s#xual fluidity among women. This has to do with the stresses of living as co-wives in polygamous marriages involving several women and one man.
As you can imagine, life must feel pretty lonely when your s#x life is only scheduled for Tuesdays. It makes sense that women would look to their co-wives for comfort, “therefore reducing conflict and tension inherent in such marriages while at the same time successfully reproducing with their husbands in heteros#xual unions,” Dr. Kanazawa says,
Rather than being straight or gay, to whom women are s#xually attracted may depend largely on the particular partner, their reproductive status and other circumstances.
This theory may also provide the missing puzzle piece in other facets of human s#x research, including the differences between male and female homos#xuality, arousal and menstrual synchronicity. Finally, someone besides cosmic fortune tellers might be able to explain why everyone in the office starts trading tampons around the same time of each month.