Lucretius treats male desire, female sexual pleasure, heredity, and infertility as aspects of sexual physiology. In the Epicurean view, sexuality arises from impersonal physical causes without divine or supernatural influence. The onset of physical maturity generates semen, and wet dreams occur as the sexual instinct develops. Sense perception, specifically the sight of a beautiful body, provokes the movement of semen into the genitals and toward the object of desire. The engorgement of the genitals creates an urge to ejaculate, coupled with the anticipation of pleasure. The body's response to physical attractiveness is automatic, and neither the character of the person desired nor one's own choice is a factor. With a combination of scientific detachment and ironic humor, Lucretius treats the human sex drive as "muta cupido", "dumb desire", comparing the physiological response of ejaculation to the blood spurting from a wound. Love "(amor)" is merely an elaborate cultural posturing that obscures a glandular condition; love taints sexual pleasure just as life is tainted by the fear of death. Lucretius is writing primarily for a male audience, and assumes that love is a male passion, directed at either boys or women. Male desire is viewed as pathological, frustrating, and violent.