Dr. Steen is primarily a popular science writer, trying to enlighten outsiders who would like to know more about some of these important matters, rather than writing for those already in the know, and most of what he deals with derives from secondary sources. In this he does quite a good job, considering that there are as yet few firm answers to many of the difficult problems arising.

The first part of the book gives a clear and well-written account of some of the methods available for sorting out the parts played by genetical inheritance ("nature") and the environment ("nurture") in determining the human condition, by "split twin" studies, and so on. Dr. Steen here is highly critical of the "dark history of eugenics", giving an interesting account of how what were originally, and indeed still are, Francis Galton’s sensible suggestions were perverted in the 1920s in the USA, and of course most of all in Nazi Germany. "Eugenics" has now become almost a dirty word in progressive circles, which is a pity since it simply means "good breeding". Now that the harsher forms of natural selection are no longer allowed to operate, it is all the more important to try to maintain and better our genetical inheritance, and to check any possible decline, by selective breeding. And that can be done by perfectly acceptable legislative and other means, as Galton and the other early eugenicists proposed.

We then come to the controversial question of the inheritance of intelligence, of which some substantial part is genetical and therefore determined at conception. But a lot of what is measured by IQ testing certainly results from "nurture", including education etc, and is acquired after birth. Here Steen takes the politically correct line on the Bell Curve in concluding that its "social programs are intellectually bankrupt and morally indefensible; they resolve nothing, they merely validate an inclination to ignore the problem." But he does add that "the most critical reviews ... are simply an emotional denial of the book, without a serious consideration of its contents", although he doesn’t himself attempt any critical discussion of where and why the facts and arguments in The Bell Curve are wrong. See my own review in the Newsletter of June 1995 for another point of view.

The second half of the book is concerned with the inheritance of disease, and of behaviour including mental disorders, sexual orientation, alcoholism, crime and violence, etc. But this is perhaps less satisfactory since, although susceptibility to some diseases, including cancer, can be shown to have significant genetical components in addition to equally and usually more important environmental effects, that is seldom so for any of the behavioural characteristics discussed. Of course, few biologists would doubt that genetical inheritance has a part to play in most if not all of these, as indeed it does in almost everything else, but what this is, how it operates, and what can be done about it, is usually at present far from clear.

The final chapter, on Biology and Social Responsibility, is concerned with what, if anything, we ought to do with biological information which may affect individual people, adversely or otherwise. It is already possible to assess the genetical risk of developing quite a few serious diseases, and the number of these is likely to be greatly increased when the Human Genome Project produces its results, which should be quite soon. This will have serious implications for employment and insurance, for example, if it were possible to predict that someone was likely to die prematurely of some identifiable disease. If a Life Insurance company, as part of the medical examination already required, demanded a report on the proposer’s genetical susceptibility to disease, why should this be refused if the information was in fact available? And would it serve any useful purpose to know if you were going to suffer from Alzheimer’s senile dementia in old age?

It should soon be possible to ascertain if someone is carrying genes for a whole variety of serious diseases, which will be quite asymptomatic if they are recessive, as they usually are, and which will show their effects as recessive homozygotes only in future generations. Some might say that the carriers should not be allowed to have any children, which will eliminate their defective genes. But, once the Human Genome Project really gets going, almost everybody will probably be shown to have some very rare harmful recessives in their genotypes. Furthermore, although Dr. Steen doesn’t mention the possibility, at least some of these recessives may be maintained in the population by overdominance effects, with the heterozygotes being actually fitter than the normal homozygotes: and one would hardly want to get rid of them. There are obviously some very difficult ethical and practical problems here, which we or our near descendants will have to face up to soon enough.

C B Goodhart