Jewish history." Goodfriend speculated the priesthood excluded women because of "fear that the sudden onset of menstruation would result in the clash of impurity and holiness, with presumed dire consequences." Goodfriend noted that these laws and associated customs affected both women's public religious life and private family life, as they and their husbands were prohibited from sex for extensive periods of time, affecting their fertility and married life in general. Professor Shaye Cohen of Harvard University noted that the only element in common between the “ritual” or physical impurities of and the “dangerous” or sinful impurities of is intercourse with a menstruant. Leviticus chapter 13 Professor Ephraim Speiser of the University of Pennsylvania in the mid 20th century wrote that the word “Torah” () is based on a verbal stem signifying “to teach, guide,” and the like, and the derived noun can carry a variety of meanings, including in , , 54, and 57, specific rituals for what is sometimes called leprosy. Speiser argued that in context, the word cannot be mistaken for the title of the Pentateuch as a whole. Commandments According to Maimonides Maimonides cited verses in this parashah for 3 positive and 1 negative commandments: To circumcise the son, as it is written "and on the eighth day the flesh of his foreskin shall be circumcised" For a woman after childbirth to bring a sacrifice after she becomes clean, as it is written "and when the days of her purification are fulfilled" Not to shave off the hair of the scall, as it is written "but the scall shall he not shave" For the person with skin disease to be known to all by the things written about the person, "his clothes shall be rent, and the hair of his head shall go loose, and he shall cover his upper lip, and shall cry: 'unclean, unclean.'" So too, all other unclean persons must declare themselves. According to Sefer ha-Chinuch According to Sefer ha-Chinuch, there are 5 positive and 2 negative commandments in the parashah: The precept about the ritual uncleanness of a woman after childbirth A ritually unclean person is not to eat meat of holy sacrifices. The precept of a woman's offering after giving birth The precept regarding the ritual uncleanness of a m'tzora (person with skin disease (, tzara'at) The prohibition against shaving the area of a nethek (an impurity in hair) That one with