[from Kent R. Lehnhof's essay, “‘Impregn’d with Reason’: Eve’s Aural Conception in Paradise Lost.” Milton Studies 41 (2002)]
Relying upon such classical authorities as Galen and Aristotle, the early moderns asserted the existence of a female seed analogous to the male semen. Although the female seed was believed to be weaker and less pure than the male seed, it was nevertheless considered vital for conception. Conception, it was thought, could only occur if both the male and the female seeds were discharged during the sexual encounter. Because they believed that a female only emits her seed upon attaining orgasm, the early moderns insisted that conception could only come about if a woman enjoyed the sexual act. Thus, conception came to constitute concrete proof that a woman acted as a desiring, consenting participant in any given episode of intercourse. This putative connection is codified in Renaissance rape laws. As Sir Henry Finch professes in the enormously influential Law or a discourse thereof (1627): "Rape is the carnal abusing of a woman against her will. But if she conceives upon any carnal abusing of her, that is no rape, for she cannot conceive unless she consent." Richard Burns reiterates the idea in his guide for English magistrates, citing classical authorities to establish that "a woman can not conceive unless she doth consent." According to Thomas Laqueur, the belief that pregnancy proves complicity was so entrenched in English society that its physiological basis was not even questioned until the second half of the eighteenth or the first half of the nineteenth century.