Chapter four in our text begins with the excerpt, "Research suggests that we can unconsciously smell each other's fertility, mood, and genetic compatibility." When I first read this line I happen to be on a plane and the gentleman sitting next to me suggested that the whole chapter would be about sex. Not that I disagreed, but being that the book is based on our perceptions, I try to think about what each chapter may discuss, and then compare my thoughts of what I thought it would be to what it actually was at the end of reading it. Needless to say, he was more so correct than I was. Anyway, I found this chapter really interesting, so I researched a bit more to see what I could dig up by searching the phrase "unconsciously smelling each others fertility," which is a weird enough statement alone. I actually found a pretty good article by Christiane Northrup M.D. titled Wisdom of the Menstrual Cycle. What I took from it is that our bodies follow cycles of the moon, by similarly going through phases of darkness. During those rotations, our bodies perceive things in different ways because of our heightened senses. At that time females experience both a biological and physiological cleansing. The article suggested that if we follow our body’s wisdom when it goes through these phases, we would be less stressed. Overall, premenstrually, women are more in tune with their body. We perceive things much more intensely and the "veil" between the conscious and unconscious is very thin. The phase from ovulation until the onset of menstruation is when women are most in tune with their inner knowing and with what isn't working in their lives.
Please see the attached link to read the article yourself.