A s far back as the biblical story of Adam and Eve, people have understood that human reproduction is the result of sexual union between a man and a woman. Over the centuries, however, theories on exactly how it occurs varied wildly. The early Greek physicians Hippocrates and Galen believed that the male and female reproductive organs were opposite counterparts of each other in form but similar in function, both producing semen or “seeds.” Conversely, the Greek philosopher Aristotle posited that the male contributed the human essence and the woman provided only the physical matter that nurtured that essence into an infant. Even as late as the 17th century, scientists continued to argue over whether the human being was formed from an egg or from a miniature human “ani- malcule” in the sperm.

aToday it is known that reproduction occurs through the joining of an egg, contributed by the female, and a sperm, contributed by the male. Much more is known, too, about how that initial fertilized egg develops during pregnancy. In fact, scientists’ understanding is now so complete that doctors fertilize eggs outside the body, or “in vitro,” to help treat certain types of infertility. Pregnancy can even be prevented through a variety of birth control methods. But as science advances in the understanding of human reproduction, it also leads to new ethical and societal issues that must be resolved.

This book explores both the science and the social issues surrounding the human reproductive system. The differences between the male and female reproductive organs are highlighted, in addition to the different hormones controlling their development and function. The book outlines the process of reproduction and how the fetus develops, as well as issues that can interfere with those processes. Ethical debates range from birth control to infertility treatments.