 Until approximately the mid-19th century, philosophical views on the fetus were influenced in part by Aristotelian concept of delayed hominization.According to it, human fetuses only gradually acquire their souls, and in the early stages of pregnancy the fetus is not fully human.Relying on examinations of miscarried fetuses, Aristotle believed that male fetuses acquire their basic form at around day 40, and female ones at day 90.