Science and science journalism are different things. Though each is valuable, they require at least partly different skills. Science demands unrelenting skepticism about purported facts and theories, and science journalism demands an ability to make the complex clear. Despite my admiration for his work as a journalist, I’m afraid that Nicholas Wade’s latest book reminds us of the risks inherent in blurring the distinction between these endeavors. A Troublesome Inheritance goes beyond reporting scientific facts or accepted theories and finds Wade championing bold ideas that fall outside any scientific consensus.

Wade, now a freelance writer and reporter, is best known for his work as a journalist atThe New York Times. He has also written several popular books on biology. The most recent—Before the Dawn (2006) and The Faith Instinct (2009)—focused on evolution in human beings, including the evolution of religion. In A Troublesome Inheritance, Wade maintains this focus on human evolution, though he turns to a far more controversial topic, human races. His goal, he says, is “to demystify the genetic basis of race and to ask what recent human evolution reveals about history and the nature of human societies.” He concludes not only that human races are real but that they probably differ genetically in surprising ways.

Wade’s main claim is that human races likely differ in social behavior for genetic reasons as a result of recent evolution. These slight differences in behavior may, in turn, explain why different sorts of social institutions appear among different peoples:

Institutions are not just sets of arbitrary rules. Rather, they grow out of instinctual social behaviors, such as the propensity to trust others, to follow rules and punish those who don’t, to engage in reciprocity and trade, or to take up arms against neighboring groups. Because these behaviors vary slightly from one society to the next as the result of evolutionary pressures, so too may the institutions that depend on them.

Evolutionary biology might therefore have something to say about why some peoples live in modern states and others in tribal societies, and why some nations are wealthy while others remain mired in poverty.1

The science in A Troublesome Inheritance is mostly inspired by the genomics revolution of the last decade or so. (A genome is the full complement of DNA, the hereditary material, that an individual carries.) This revolution has been, to a considerable extent, a technological and economic one. The high-tech approaches needed to “sequence” a person’s genome—to decipher the three billion units of DNAthat make up a human genome—is now sufficiently automated and inexpensive that geneticists have sequenced the genomes of thousands of people from around the world. In the course of this work, results have emerged that throw light on racial differences. Geneticists, Wade says, have been reluctant to talk openly about these results, which are sometimes politically sensitive. He takes up this task here.

A Troublesome Inheritance cleaves neatly into two parts. The first is a review of what recent studies of the genome reveal about our evolution, including the emergence of racial differences. The second part considers the part that genetic differences among races may play in behavior and in the social institutions embraced by various races. These two parts fare very differently....