The old Aristotelian idea that females were imperfect males was still assumed to be true in seventeenth-century Europe. The modern science of biology, which established two distinct sexes, was still in the future. Although eighteenth and nineteenth century sexual distinctions based on biology supported the idea that the capabilities of women were inherently limited and inferior to those of men, they at least focused on the distinctness of male and female identities.

The Aristotelian view has been called the “one sex theory.” Many serious and well-regarded theorists of the human body solemnly insisted that the female reproductive system was no more than an inverted form of the male one. Like Aristotle, they believed that women were naturally colder and damper than men, besides being in every respect weaker. Moreover, women were considered to be the sex-desiring, aggressive gender, whereas men were often viewed as helpless and vulnerable in sexual matters.

Medical opinion concurred that blood, semen, and spinal fluid were all the same basic vital substance or fluid, albeit in different forms. Sexual intercourse was not only often viewed as a weakening form of physical dissipation, but male ejaculation was believed to draw brain tissue down the spine and out the penis—a very strong reason for a male philosopher to remain celibate. Moreover, women were viewed as the source of venereal disease, unwanted children, and burdensome financial obligations. So great was their negative sexual power held to be that they were at the same time also presumed responsible for male impotence.