Y: the Decent of Men: The Descent of Men (Hardcover)

Having said that Y is a cracking read which takes the author's ruminations on the nature of masculinity way beyond his specialist area of genetics.

Steve Jones has a real talent for rendering fairly difficult scientific concepts both interesting and digestible, even for a science dullard like myself.

The book contains a leg crossing chapter on circumcision (which he contends, rather controversially, is a form of ritualised child abuse) as well as castration and other forms of mutilation. The hard facts about erection are revealed, as well as discussions of new research into sexual behaviour, penis size and sperm donation.

Aside from the welter of sexual statistics from the animal kingdom, eg the Zebra who emits half a gallon of sperm in a single ejaculation, Jones contextualises human sexual behaviour and anatomy by comparing us with our animal cousins and draws some surprising conclusions about the innate sexual nature of humankind.

This book is really the antidote to the kind of woolly 'Men are from...' type pop-psyche nonsense that abounds these days. Jones presents the facts as he sees them based on current research and avoids drawing spurious conclusions. His discussion of the genetic basis of Homosexuality seems to end with a kind of 'but we're still not really certain at the moment'.

Of course Steve Jones is a man and so am I so there is an inevitable bias, but this seems like an exceptionally even handed discussion of masculinity, if Jones isn't certain then he leaves the questions open, and the book is all better for it. Y doesn't contain the kind of radical central thesis that propels a book to the top of the bestseller lists, but for those interested in a readable account of the research as it stands it is indespensible.

Jones opens his account with a touch of irony - it was a woman, Nettie Stevens, who identified the male chromosome in 1905. It took nearly a century to perceive the gene controlling sex determination - the SRY [sex recognition gene]. From there Jones explains the role of that short, 20 gene DNA string and its impact. Embryo development relies on sperm-borne chemicals. This input is part of the reason maleness drives the pace of evolution. Sperm is an invader, and the body resists invaders. The chemical changes reflect that fundamental dichotomy and there's nothing universal about male sperm. Its variety reflects the rapid evolutionary pathways taken by various organisms. And few species have evolved as rapidly as humans, Jones reminds us.

That haste, however, has led to vulnerability. Male lines, particularly in our own species, die out quicker. Jones' example is expressed in the recognition that all the family lineages since William the Conquerer had died out. Nor are his examples confined to humans. Hermaphroditic slugs in the French Pyranees are exhibiting an increase in female-only lines. Given his evidence for this happening in modern men, one can only wonder at the cause of this unisex phenomenon.

For it's modern men that are the target of this book. Whatever forces in evolution have reduced the size and impact of the Y chromosome, modern civilization has exacerbated its decline. Clinics in various nations record reduced sperm counts, notably in Italian taxi drivers, American businessmen, Scots shopkeepers. Jones isn't applauding these trends as some proto-feminist. He wants, through this book, for males to become aware of the fate their descendents will confront. Maleness is likely to disappear, and offers pointers to prevent that extinction. More focus, he stresses, needs to be made on the impact of various foodstuffs and industrial chemicals.

Depressing as much of this sounds, there is much to be learned from this book. Jones' ability to impart good science in a readable style makes this book an ideal acquisition. While facts galore are presented here, pedantic stumbling blocks are not. He has no more axe to grind than the desire to increase our awareness of ourselves, both male and female. As he notes, understanding of the operations of sexual mechanisms is still in its infancy. This book will stand for some time until more of our body's hidden secrets are revealed. For we men, let us hope it's not too late.