You have to much time on your hands to be worried about this. Why not just be happy that you don't have a menstrual cycle to be pained by or to worry about? I will repeat what I said before. Menstrual blood is a magical ingredient to many POWERFUL magical practices of the pre-Abramic (Judeo/Islamic/Christian) cultures, this is the foundation of your obvious fears. No one wants to talk about that. Women have never been unclen for what comes naturally to them. Your reasoning attempts to confine, control and supress women, I don't care what book it comes out of. Menstruation is anormal fact of life, and it is your CHOICE to be or not to be around a woman during that time, but don't make her out to be unclean.