Despite the face that roughly half of humankind menstruates for much of their lives, the topic still carries a certain taboo, and many myths surround it — including in the science about it. We're revisiting our conversation with University of Illinois Professor Kate Clancy, whose book is "Period: The Real Story of Menstruation."

Despite the face that many people menstruate at some point in their lives, the topic still carries a certain taboo, and many myths surround it — including in the science about it. The author of new book that tackles those topics joined The 21st to discuss menstruation, the evolving science around it, and the stigmas still associated with it.