The title of this book is an obvious sore point but I bought the book anyway. The author is relatively honest and admits on page 8 that using the term “God gene” is a “gross oversimplification” although on the next page he deems it “a useful abbreviation of the overall concept”. The subtitle zooms in “How faith is hardwired into our genes”. To be really informative the title should be “About the genetic components contributing to spirituality”. That certainly would avoid the need to define God, resulting in more honest science-writing at the ‘cost’ of’ useless polemics. But there probably is a link between the title and a cluster of money genes expressed among the publishers?

All this may sound as nitpicking about definitions but unless you seek polemics instead of enlightenment it is good practice to be as clear as possible. And this is at major problem with this book, the words god, religion, religious practice, faith, transcendence, self forgetfulness are intertwining themes that are not always clearly demarcated.

As an aside defining what ‘a gene’ is, is not that trivial, where does ‘a gene’ start and stop, counting genes is therefore not easy and not that interesting either (humans have x genes but mice have only slightly less and so on).
At the end of the first chapter Hamer explicitly adds some caveats and limitations, a recommendable practice indeed! Read them twice.

Chapter two starts with the main trust of the story: how do we measure faith, or more precisely ‘self transcendence’. This is mainly done through questionnaires and Hamer elaborates on the history and people behind these tests. Hamer himself uses the word ‘flaky’ in the context of defining ‘ self transcendence’ and being a skeptic I was not convinced by the data in the book, a position that was only reinforced by my current reading of Ann Murphy Pauls recent book.

The book subsequently elaborates on ‘the genetic component’ as estimated from twin studies. These studies, although not full-proof, are quite impressive even if the number of twins studied is not very big. But twins, even when they are separated at birth, still share the same environment before being born. How to subtract these common environmental effects from the shared genetics is however not discussed.

Next Hamer describes how, through some clever DNA technology, they could zoom in on a candidate gene: VMAT2, one of the presumed many. Although these sections of the book are rather interesting from a pharmacological and neuroanatomical point of view, it does not live up to the expectations raised by the title. I find the fact that a gene can influence spirituality far from unexpected. What happens in our brain is heavily influenced by our biology… and our chemistry… and our physics. (If you disagree, drink a couple of beers or knock yourself on the head with a hammer it will surely influence the functioning of your brain and your spirituality). Hamer interprets the data as if there is an unique link between this particular gene and the outcome of a particular questionnaire and between the questionnaire and faith (… or God). That is obviously a tall order but an otherwise totally reasonable hypothesis. Some more evidence would certainly be welcome however.

The last chapters of the book are a mixed bag. Some interesting genetics of particular populations, clearly shows that sociocultural religious practices can have an effect on genetic inheritance and therefore provide a model of how spirituality and religious memes got intertwined during evolution. Again, a nice illustration, but nothing unexpected. A lot has already been written about the evolutionary advantages of religion and Hamers take on the story is rather odd. He makes a big fuss about the supposedly big differences between E.O. Wilson an R. Dawkins ideas on ‘religion’, but fails to see that these authors were discussing different things. (In the US Dawkins bashing is probably bon ton these days…) A particularly sore point is the how the evidence about the presumed beneficial effect of prayer is described. Extraordinary claims need extraordinary evidence and one headline grabbing positive result should still be replicated and interpreted in the context of existing evidence. This web-page should convince you some more skepticism is only healthy, note that two studies were later exposed as apparent fraud.

In the last chapter Hamer desperately seeks a happy end, some kind of truce between science and religion. He does this in part by stressing the difference between spirituality and religion, a confusion he happyly exploits in the title of the book. But it is too early for such an overarching synthesis, the data is simply to fragmentary, the hypothesis too vague and the biology in between genes and behaviour not yet explored in enough depth. And it would not hurt to give the work of M. Persinger or Ramachandran a more prominent place in the outlines of such an overall sysnthesis.

Should you therefore ignore this book? No, certainly not, and certainly not if the title offends you at first glance. You may learn some interesting genetics, pharmacology and neuroscience. For consilience you should look elsewhere.