The one-child policy in China is one of the most controversial policies ever proposed to limit a country's population growth, and its continued implementation is the source of much scholarly debate. While scholars have done extensive studies of the policy's negative impacts such as skewed sex ratios, coercive abortion, and the increasing burden placed on younger generations to care for their elders, little has been done to study the origins of the policy and to explain how such stringent restrictions on family size emerged. In this book, Susan Greenhalgh offers the first in-depth analysis of the scientific debates that eventually led to the adoption of the strict one-child policy in China. She chronicles the different political and scientific trends to explain why and how the political elite settled on a single-child policy as the best solution for controling population growth. As one of the leading experts on population policy in China, Greenhalgh is well suited to take on such a study, using ethnographic research to piece together the behind-the-scenes debates among three competing scientific groups. The result is an informative and innovative analysis of the one-child policy that offers insight into the unlikely group of scientists responsible for it, the rather dehumanized and empirical slant to its implementation, and the dangers of science as a driving force for public policy.

The book's main contributions are its development of the theoretical and political context in which population policy must be understood in China, and its detailed examination of the relevant scientists and scientific debates. It is also worth noting that inquiry into the policy's origins, the focus of the entire book, technically falls into one of several “forbidden zones” in China, which places certain topics off-limits to discussion (p. 4). Greenhalgh states that even insiders and those actually involved (scientists, population intellectuals, and officials) never really knew the full truth; thus, the purpose of her book was to fit together these missing pieces and create a comprehensive picture of the policy's origins (p. 42). At the most basic level, the policy's date of implementation is even contested, and it is the source of some confusion. Therefore, the author's detailed account of scientific conferences, political meetings, and statistical debates is a significant and unique contribution to the study of population policy in the Chinese context and the first of its kind for both insiders and “outsiders.”

Greenhalgh begins the book with what she calls an epistemic approach to policymaking, bringing together governmentality studies and science and technology studies, with attention to social constructivism. Her approach is one that blends these two: “the broad framework for understanding power, policy and politics and the constitutive role of knowledge in these domains” and “the micropolitics by which policy-relevant knowledge is formed and politically advanced,” respectively (p. 9). She uses this framework to examine the politics of science and the science of policy, and how “truth” was constructed by competing groups, all of which are discussed in the first two sections of the book. However, before jumping into the specifics, she first discusses the study of population in the context of different campaigns during the Mao era, and establishes the intellectual climate during that period and the lack of accurate or reliable methodology. In addition, the author outlines many of the political dynamics relevant for understanding Chinese politics, which will be helpful for those unfamiliar with Chinese institutions and the tumultuous Mao era. As she indicates from the beginning, the book is designed to be interdisciplinary and should be of interest to political scientists, anthropologists, demographers, sinologists, and a variety of other natural and social scientists alike. Thus, the book is written to be accessible to each of these audiences, and she provides the relevant background information needed for each of these groups of scholars.

At the core of the book is the categorization of three distinct groups of science scholars and the key leader in each group: the Marxian statisticians and economists (under the direction of Liu Zheng), the sinified cybernetics of population (led by Song Jian), and the Marxian humanists of population (led by Liang Zhongtang). Each group is differentiated by its views on the source of the population problem, how they see it resolved, and the type of collateral damage that comes with each. The Marxian statisticians took more of a gradualist approach to population control, encouraging smaller families and using statistics to show that China was in danger of economic backwardness based on its population trajectory. In contrast, the cybernetics were a group of missile scientists who claimed to produce positivist objective science devoid of any human or social interference, and argued that the population problem was one of simple biology where fertility was a controllable variable. Finally, the Marxian humanists examined some of the human costs to implementing population control policies, particularly the negative impacts it would have on the rural population. The battles among the three groups are outlined in Chapters 6–8, where each group tries to get its point across to the political elite and influence policy decisions. In the end, Greenhalgh shows that the cybernetics and their strict one-child policy managed to capture the attention of the top leadership, and the human consequences that were notably missing from their proposal are at the core of many problems that we see in the policy's implementation today.

While the book is interdisciplinary and tries to include a little something for everyone, at times it seems more historical and descriptive than analytical. However, this is arguably because Greenhalgh is interested in identifying the policy's origin, and not about analyzing the policy's implementation or social outcomes, which are both covered in some of her earlier work. In addition, while the scientific debates seem clear and well documented, there are still questions and more information needed on some of the political debates that occurred among the political elite in terms of the policy's adoption. Realistically, it may not be possible to answer these questions or provide this kind of evidence given the secrecy at the highest levels of decision making. Greenhalgh does argue that critics who question science's influence and claim that it is “politics not science” that dictated the policy are essentially toeing the party line and are victims of the off-limits questioning on the policy's origins. However, one can argue that the line of inquiry raised by these critics was worth at least some further development in the book.

Overall, it is clear that Just One Child offers yet another important piece for understanding the population policy puzzle in China. It offers many previously undocumented details and accounts from those connected to the policy's origins, and is a must-read for anyone interested in population policy, the politics of science in China, or the dangers to be found in scientific policymaking.