The question of whether abortion should or should not be permitted, and under what circumstances, is among the most difficult and sometimes anguished decisions for contemporary men and women. How we feel about this issue, and what actions we take, help to define our image of who we are as social beings.In The Facts of Life, Harold Morowitz and James Trefil, two distinguished scientists and science writers, examine what modern biology can contribute to our understanding of this debate. Sensitive to the myriad ethical and religious arguments beyond the realm of science that swirl around abortion, the authors focus on one crucial question--when does a fetus acquire "humanness," that quality that sets us apart from all other living things. From the viewpoint of science, they argue, "humanness" begins with the possession of a highly developed cerebral cortex. While humans are linked via cell structure and cell chemistry with all life on our planet - from monkeys to fruit flies to pumpkins - it is the human brain structure which makes us who we are. Reviewing the latest advances in molecular biology, evolutionary biology, embryology, neurophysiology, and neonatology - fields that all bear on this question - the authors reveal a surprising consensus of scientific opinion on when humanness begins.A lucid primer on the biological aspects of the abortion issue, The Facts of Life is also a fascinating inquiry, across various scientific disciplines, into what makes us uniquely human. Anyone who struggles with the issue of abortion will be grateful to find a work that moves this heated issue from the intensely emotional area it has occupied to the calmer domain of science.