[DISCLAIMER: Explicit, totally batshit insane analysis of the female anatomy]
Unlike a man, a woman is not fully functional without a man, a supplier of sperm-laden seminal fluid. His reproductive organs operate continually from puberty to death. Hers cannot function without sperm. Menstruation is a malfunction. The uterus and vagina aren’t there to spew bloody mucus out. A girl-woman who is not consciously aware of or intending to avoid procreation becomes most desirous of receiving semen during five of the six days preceding ovulation. She is most easily aroused during those days, peaking at about three days before ovulation.