"The women's menstrual cycles....."  At the time this was seriously considered as a possible cause. Well maybe it was to some degree. I'll tell you what I have experienced with little lead way for discrediting this factor. We went in, 2005, and set up a permitted camp on an island for the 10th year. Bears were always around nightly. Fishing from our boats, Walking by our cook tent and thru camp nightly. Never a problem. We set up our guide's tent and dug a deep crapper hole close to his tent because his wife would make him go with her to pee at night. We put a pop up tent over the crapper box with comfortable seat.  She arrives that evening. She was menstruating and peed in the hole and disposed of her tampon in the fresh hole, 2.5 feet deep. That night the bear came in and knocked down the tent overturned the box and reached down into the hole and pulled out the tampon. And left.  From then on she burned everything in the tent stove. The bear obviously reacted in this case, ladies.