The first thing children ask about sex is typically, "Where do babies come from?" This, the most perplexing scientific question of all time, was hailed by the ancient Greeks as "the mystery of mysteries". Throughout history the most intelligent and well-educated men and women have struggled to understand how we reproduce, and the full picture is far from complete. In the mid-17th century, a theory of reproduction - preformation - sparked a heated debate that continued for over 100 years. Preformation proposed that miniature creatures waiting to be born existed inside each potential parent much like a Russian nesting doll. It was thought that God placed these beings during Creation and predetermined the precise moment that each would unfold and exist. In "The Ovary of Eve", Clara Pinto-Correia traces the history of this much-maligned theory, ultimately revealing its critical influence on the modern view of conception. Opinion on preformation was sharply divided. "Ovists" believed that preformed individuals existed in the egg, but "spermists" argued that the locus of perfection before birth was in the sperm. This controversy ranged beyond the narrow confines of biology. Most scholars were reluctant to allow perfection to women. After all, these debates occurred in a culture which held women responsible for the Fall and original sin and which saw women as imperfect or incomplete males. Yet spermism entailed a moral dilemma, - why would God allow millions of preformed individuals to die with each ejaculate? Pinto-Correia recounts this controversy in all its complexity, revealing the religious, cultural and social climate of the day. Acknowledging that several modern authors have presented preformation as little more than an entertaining interlude in the study of reproduction, Pinto-Correia nonetheless seeks to recast preformation as an important theory with a precious legacy. Her book shows that the basic tenets understood by the old preformationists are still a crucial part of developmental biology and effect such state-of-the art techniques as cloning.