Sarah Conly argues that people have a right to have only one biological child. It is morally wrong, she claims, to have more than one child; and there are permissible ways for governments to sanction those who have more than one child. Her case is neo-Malthusian. The present world population of more than 7 billion people is not sustainable, and a drastic drop in the global reproduction rate is needed to avoid future harms caused by our children’s consumption, particularly the harms associated with global warming and the depletion of non-renewable resources. Having more than one child is therefore wrong because of the harms that will be inflicted on future people.     

The book has seven chapters. The first provides some background on population trends and consumption, and a preview of the rest of the book. Here Conly introduces the three claims implied by her thesis that people don’t have a right to more than one biological child. This sets up the following three chapters.

          The first claim is that people don’t have a fundamental interest in having more than one child. It is the focus of chapter two. A fundamental interest grounds a right to a thing only if that thing is necessary for a decent life. But since many childless people have decent lives, is there a ground here for a right to even one child? While Conly grants that there is such a ground and that there is such a right, this might not be so. Conly suggests that this challenge might be answered by pointing out that most people nonetheless want to have children and that having a child is part of their view of the good life. But since neither of these is sufficient for something to really be a fundamental interest (as opposed to just evidence that people believe it is a fundamental interest), we will have to look elsewhere for such a ground. She then explores and defends the view that the fundamental interest in having children has three components, each of which can be satisfied by having just one child: an interest in having one’s own biological offspring, an interest in rearing children, and an interest in being treated equally in matters of procreation.

          Where the first chapter explores whether a right to have more than one child might be grounded in considerations about the procreator’s well being, the third chapter looks at the possibility that it might be grounded in considerations about the procreator’s autonomous agency, and specifically their right to control their own bodies. Conly pursues a divide and conquer strategy. She argues that none of the three available ways of understanding a right to control over one’s body yields an inalienable right that cannot be overridden by great harms, like those wrought by environmental damage. One understands a right to control over one’s body as a property right, another understands it as a necessary condition on being an autonomous agent, and the third understands it as necessary for just equality. This is an especially rich chapter that also includes important discussions of the limits of religious rights and the nature of incremental harm.

          The third key subsidiary claim is the most provocative. It is the focus of chapter four. It says that if voluntary efforts to reduce the reproduction rate are not sufficient, governments have available morally permissible coercive measures to reduce the reproduction rate. According to Conly, coercive measures will only be permissible as a last resort after attempts to reduce the reproduction rate through education, availability of contraception, and use of positive incentives have been exhausted. In addition there are constraints on the kinds of coercive measures that are permissible: forced abortions and forced sterilization are not, while fines and revoking of privileges (e.g. driving) are. Conly also adds some important observations about how laws can generate social norms and she argues that laws against having more than one child are the only available solution to the collective action problem wherein extra children impose externalities on other parties.

          Chapters five and six take up two other possible avenues of resistance. Chapter five responds to three ways of resisting that make an appeal to the future: that the alleged environmental harms are not sufficiently predictable; that future people who do not currently exist lack rights; and echoing Parfit’s non-identity problem, that future people cannot be wronged as long as their lives are worth living. Chapter six reviews, and measures roughly just how bad, the following possible bad side effects of population control are: deleterious effects on the economy, exacerbation of sex selection, extinction of cultures, and harms to children because they don’t have siblings. In each case, Conly suggests other measures that can be taken that in combination with her proposed limits on procreation will adequately minimize these bad effects. Chapter seven wraps things up with a look at other values that might be at stake besides harm to future humans, including the intrinsic value that might reside in natural non-human entities.

          Let me end with one criticism. Conly’s overall approach involves holding fixed all factors that determine our damage to the environment, including our rates of consumption, the amount of greenhouse gases we emit, and our technologies. Keeping all these factors fixed, she then argues that many of us should have fewer children. But of course we might try to change any, or all, of the factors. What we need are moral assessments of more global strategies for avoiding the enormous future harm that we will cause if we don’t change anything. Each of these strategies will target one or more factor for change, and specify recommended means of changing those factors. To illustrate, consider the following strategy for avoiding one important kind of environmental damage that one’s children might cause: offsetting greenhouse gas emissions. For very little money, by many estimates just a few hundred dollars per year, a person who consumes at average first-world rates can pay to prevent the release of the same amount of emissions of greenhouse gases that their consumption resulted in. The result is that they have no net impact on climate change. If someone has three children but also commits to offset each child’s emissions each year they are alive (they can set up a trust fund to do this, or they can offset it all upfront), then those children will have no net emissions over their lifetimes. Their children will have the same impact as the green couple who forego having any children, and less impact than the couple who follow Conly’s moral advice and have just one child. This makes vivid something we already know: the number of children that one has is just one cause, alongside many others, of environmental harms; and the number of children that one has is neither necessary nor sufficient for any particular environmental impact. What we really need then is to compare global strategies, each of which is a combination of strategies that target one or more causal factor, to get anything like a definitive assessment of what we morally ought, and morally ought not, to do.

Still this is a well crafted book on a very important topic. And while it covers many of the empirical and normative topics that intersect with it, many readers who specialize in applied and normative ethics will find a lack of detail at important turns in many of the arguments. It is probably laypersons and undergraduate students who will benefit the most from reading this book.

© 2016 Peter Murphy

Peter Murphy, Department of Philosophy and Religion, University of Indianapolis, murphyp@uindy.edu