Taboos against menstrual sex are probably rooted in an inchoate understanding that there is less likelihood of conception during menstruation. If procreation and tribal survival are the goals, then delaying sexual congress until ovulation makes sense, especially if the men and women involved are going to be reliably available to one another continuously. But, what if the window of sexual availability is open for a limited amount of time; what if it could close at any moment—permanently?

This is the situation facing men and women during war time mobilization. Soldiers are given brief furloughs following basic training before new assignments or prior to being deployed to a war zone. Such leaves are fraught with anxiety and questions: How long will the man be gone? Will he be wounded? Will he come back alive? The emotional stress of the moment is profound.

There is no way to know if couples in ancient cultures set aside menstrual prohibitions when faced with forced separations. Were love, sexual desire, and fear of loss stronger motivators than taboos and social conditioning? However, there is evidence that in mid-20th Century war times in the USA women were subtly encouraged to set aside any reluctance to engage in sex during their periods. In fact, doing so was framed as a patriotic duty, along with being a reliable worker in the defense plants. The evidence resides in a series of print ads widely distributed in popular magazines shortly after World War II began.

An entire campaign for Kotex products was built around the idea that women should be socially, romantically, and, by implication, sexually available to men home on leave from military service regardless of the status of their menstrual cycle. The most blatant example is an ad that appeared in Woman’s Home Companion and other women’s magazines in 1942 with the provocative heading, “You’re the fun in his furlough.” At the bottom of the ad we see two women working at a defense plant, a job that is made to seem doubly exhausting if the working woman has her period. Her problem is that her boyfriend is home on leave this night and she is thinking she just can’t go on a date. But it’s Kotex to the rescue. She can avoid being “a deserter” (at least it stops short of suggesting she’d be a traitor) if she’d only use the right menstrual product.

The sexual imagery in the ad is remarkably bold as she flaunts the labial folds of her gown and his penis/saber rises to her. The messages of the ad are quite clear: 1) this glamorous woman is menstruating and wearing a Kotex pad; 2) her boyfriend soldier is on leave for a short time; 3) both parties are sexually aroused; 4) they will engage in sexual intercourse this night despite the fact that she is menstruating; 5) the woman has a patriotic duty not to let her period get in the way of his sexual desire.

It is not surprising to think that sex would trump custom and tradition in circumstances such as the one depicted here. What is of greater interest is whether or not once the taboo had been defied in response to the threat of loss in the context of war the participants felt less inclined to return to the traditional ways once peace and stability had been reestablished. That challenging piece of research is yet to be undertaken.