Mark Bold

Perhaps Bryan Sykes, an Oxford Professor of Human Genetics, started out on this book by attempting a serious study of the Y-chromosome, and the ability this gives geneticists to trace paternal descent and the groupings and origins of the common male ancestors of all people on the planet. He had achieved a similar study of mitochondrial DNA and our common female ancestors with The Seven Daughters of Eve. But this time maybe the publishers insisted that he rewrite his manuscript with a slightly hysterical style, speculate about how men are doomed, and slap the dystopian title Adam’s Curse, A Future Without Men (together with a misleading picture of monkeys becoming men becoming women) on the front cover. The result is a strangely uneven mix of scientific explanation and wild speculation.

Sykes begins his description of the Y-chromosome in a personal style, tracing the way he analysed his own DNA and that of other men with the surname Sykes to find that almost all of them shared a single male ancestor who had lived in a tiny Yorkshire hamlet centuries ago. Like surnames in a patrilineal society, the Y-chromosome is passed through generations only by men. All other chromosomes in the human genome allow their genes to recombine and draw together DNA from each parent in each new generation, but Y-chromosomes remain unchanged, apart from rare mutations. Sykes’ story tries to unravel why this is so, and just what the Y-chromosome does. He draws us through the intense scientific work it required to identify the fact that it is the presence of the Y-chromosome in human DNA that causes an individual to be male, and just which gene on that chromosome it is that triggers the change in the development of an embryo from the default sex - female. It is a fascinating tour of the biology of sexual determination, removing the assumption that all life has a single gene somewhere that makes males or females. The blue-headed wrasse, a fish of the Pacific coral reefs, for example, can change its sex at will, and the offspring of alligators and turtles will become male or female depending on the temperature of their eggs’ incubation. This naturally leads onto a discussion of why species are divided into sexes, and the importance of this division for sexual reproduction and the recombination of DNA as the engine of genetic diversity, which in turn allows natural selection and hence evolution.

Perhaps the original manuscript ended here, because something strange happens. Suddenly, Sykes is possessed by the spirit of the Hamilton-Dawkins “selfish gene” idea. He arrives there via some clumsy rhetoric (”Genes could have their own ambitions.” [p132]) seemingly aimed at disproving the existence of altruism in a beehive, and consequently goes wild with a directionless spray of metaphors taken from wars and battlefields. Instead of using science to explain what happens, he too easily falls into the common pop science trap of assuming motive where really there is none: Y-chromosomes are trying to eradicate females, as they can only be passed on through the male line. Somehow, they may have the ability to force more males than females to be born in certain genealogies. But it is women who are really the cause of this murderous intent. It is sexual selection, the supply and demand economics of sperm distribution in a world of limited eggs, that causes this war. In fact, it causes poverty and the destruction of the environment, as women choose men with wealth and power as their mates, and this concentration of resources in the hands of successful men has led to massive disparities of capital. And, since the agricultural revolution, these selfish demands have taken their toll on the finite resources of the Earth, leading to our present perilous situation. At one point in the book, Gaia wakes with horror to see the damage men have done to the planet in their competition for females, and begins to take revenge on them. Sykes certainly plays fast and loose with his imagery and facts in an attempt to whip up a hysterical sense of this war having a tragic outcome for men.

Then suddenly, he returns to his original calm tone, and explains how he has used the Y-chromosome to trace common male ancestors of men in different parts of the world. The results of this research give a fascinating picture of the histories of populations throughout the globe, and especially the impact of European imperial ambitions. While maternal ancestries of men in Polynesia, for example, show local common female ancestors, the Y-chromosome study showed how there was a strong European presence in the common male ancestors. The sailors and traders and missionaries visiting the islands would have all been male, and through rape or their marriageable status as Europeans, their Y-chromosomes soon had an impact on male genealogies. The findings are repeated around the world, where common female ancestors are almost always local, but there is a significant European presence in paternal lines.

But Sykes then returns to his hysterical manner to explore homosexuality and the future of men. Homosexuality puzzles him, he says, because studies of twins seem to show a genetic factor, but how can it be genetic when homosexuality in general does not result in offspring. While a gay gene was infamously identified in the 90’s, the research was later found to be flawed. But Sykes revisits the data, and suspects that homosexuality may be passed on through maternal mitochondria. Using the selfish gene idée fixe, he presumes that mitochondrial DNA would prefer daughters to sons, as it can only be passed through female generations. His language reaches new heights of sensationalism - “if she failed to kill her sons in the womb, failed to crush the Y-chromosome during its most vulnerable nine months when she carried it within her own body, then she would see to it that it got no further. She would turn her son into a homosexual.” [p327] While the imaginative leaps may be entertaining in their flights of utter fantasy, passing through brain structure, thumb-sucking, handedness and the length of fingers as scientific explanations, we’re left dazed by the end of the outburst as the conclusion is drawn - “That would elevate male homosexuality to a true piece of genetic altruism” [p334] in the way it assists the enemy selfish genes of female-only lineages.

Not that it can make a difference to the disappearance of men, it seems. Sykes calculates that the worn-out Y-chromosome has about 125,000 years of life left before it is incapable of producing fertile men. In the meantime, environmental factors seem to be leading to a collapse in sperm counts. Fertility levels have fallen so much that these days men produce the same number of fit sperm per day as do hamsters. The little swimmers are in a bad way. It looks as if the ability to produce fertile sons is gradually disappearing. Would this lead to a world without men? Obviously not, as sexual reproduction relies on two sexes to continue the species. So, what if we create babies combining the DNA from two eggs instead of an egg and sperm, and have a world, although needing artificial conception to reproduce, that does not need men? It is possible through scientific intervention. Or, and now Sykes’ tone becomes more like Dr Strangelove, why do we not move the male sex gene (and associated gene sequences necessary for fertility) from the Y-chromosome to somewhere else in the genome, and create a healthy “Adonis chromosome”? His reasoning has the heady idealism of someone trying to create the best of all possible worlds, a terrifying prospect for us imperfect individual men.

SYKES, Bryan (2004) Adam’s Curse, A Future Without men, London: Corgi