The American Voice 2004: A Pocket Guide to Issues and Allegations Issues and Allegations: Abortion and Contraception

In determining whether to impose restrictions on abortion many cultures took into account the age of the fetus. The most influential scholar of ancient times, Aristotle (ca. 350 BC) developed a gestational time line that proved remarkably durable. Aristotle believed embryos pass through three distinct stages: 1) the nutritive/vegetative stage, characteristic of plants; 2) the sensitive stage, characteristic of animals, and, finally; 3) the intellectual/rational stage, where it becomes fully human. He maintained that the male fetus reached the recognizably human stage at about 40 days while the female arrived at that stage in 80-90 days.[2]