More Than Genes: What Science Can Tell Us about Toxic Chemicals, Development, and the Risk to Our Children by Dan Agin. Oxford University Press, Oxford, 2009; 416 pages, ISBN 978-0-19-538150-4, hardback, $27.95.
This book is a warning to take seriously toxic material in the environment because of its effects on human development even in very small amounts. A molecular geneticist at the University of Chicago, the author sets the stage by describing the development of the fetus and its brain, ranging from the history of the subject to the latest scientific findings. The book contains many notes throughout for the reader who wishes to find more source material on the information provided.
The author then turns to how the expression of genes is shaped by pre- and post-natal environmental factors, in particular the many chemicals that impact the fetus: industrial toxins and endocrine disrupters, recreational drugs, stress and other maternal hormones, etc. He argues strongly against the idea that genetic inheritance represents an individual's destiny or can be used to explain everything about a person and their life, or about human societies and customs. For example, he analyzes the flaws in many twin studies that are used to bolster a genetic explanation of phenomena but that do not take into account the pre-natal influences the twins shared.
Another concern is the many detrimental effects of poverty on human physiological and psychological development, both prenatally and throughout the lifetime. One chapter debunks the idea that IQ or intelligence differs because of race or other genetic factors, but instead is largely attributable to differences in toxin exposure, prenatal care, cultural behavior, and poverty among groups around the globe. In this way culture is central:
"...different cultures (local, national, and global) affect different people in different ways. The pregnant women of rural villages around Rome [who drink wine daily] are more influenced by local culture than by national or global culture. The amount of lead in the soil around houses in Chicago is mostly influenced by national culture – by attitudes in the mid-twentieth century about possible dangers of leaded gasoline and current national attitudes about the task of cleaning up the soil. The purity of drinking water in Topeka, Kansas is mostly influenced by local culture – by the attitudes of local industry and local politicians and of every one else in the community. In general, the development of every individual is influenced by factors in the surrounding culture – factors that operate from conception forward, and not just after birth. No fetus develops independent of the culture around it. . . .
"...But no matter the culture, a critical phenomenon needs to be emphasized: the impact of culture on the fetal environment, one environment influencing another environment, the fetal environment translating cultural forces into biological effects that shape the development of the brain and nervous system. This connection between culture and brain development is as much anthropology as neuroscience – which makes the connection intriguing and even startling. But more important is that the connection is crucial for public policy." – pp. 265-6
Thus poverty, lower IQ, and psychological problems are "inheritable," not genetically but environmentally. And therefore, human intervention can ameliorate these tendencies if people have the political will to do so. As the author states in his conclusion:
"What I have tried to elaborate in this book is the reality that no fetus develops in isolation from the community around it.
"The most important consequences of this reality is that every fetus is exposed to environmental effects that have the potential to shape, divert, or derange its development. And that potential can have far-reaching effects on that child's brain and behavior in postnatal life. The classical idea of 'immaculate gestation' thus needs to be abandoned if we're to have a full understanding of the origins of human intelligence and behavior.
"A variety of people, including many in industry, may be opposed to the idea of the fetus as an environmental target. . . .
"As for academic controversy, it always lurks in the background. For genetic-determinist conservatives, the only IQ and behavior determinant believed important has always been genetics – with some genetic determinists even promoting the silly extreme view of innate white supremacy. It's a sorry history. I think too many genetic determinists have gone beyond reason and science in their dictum that genes rule. . . .
"But some researchers who emphasize postnatal environmental determinants of behavior have also had a mistaken drumbeat. Thirty-five years ago, some progressive psychologists dismissed the prenatal environment as an important source of group differences in IQ. They believed any focus on the prenatal environment was a genetic-determinist conservative diversion that would reduce the need for policies to address group social and economic differences. During the years, they have overlooked the fact that for most disadvantaged groups the prenatal environment is essentially controlled by social political, and economic forces. The prenatal environment routinely translates social and economic conditions into uterine biological variables that can produce transgenerational cognitive dysfunctions and deficits. Attending to those conditions adequately would benefit everyone, whether a fetus, a pregnant mother living in dire poverty, or an entire overburdened community.
"In a similar way, ... a great deal of emotional and political energy in American is exhibited by certain religious groups in their promoted concern for the life of the fetus – the life of the unborn. It's a disappointment that so little of that energy is devoted to rectifying man-made social and industrial conditions that mangle the unborn in America by the millions.
"What seems certain to me is that accepting things as they are is a defeat of the human spirit. But I don't think such defeat is necessary. I'm optimistic about what mankind can and will do to eliminate preventable fetal impacts that damage the brains and bodies of generations of children. It's a tractable problem, much of it man-made." – pp. 305-7
– Sally Dougherty (April