The male species is doomed, says Bryan Sykes, professor of human genetics at Oxford University.

And a woman-only world is possible.

It is no secret that men are basically genetically modified women. In this respect, our evolution can be regarded as a gigantic and long-running GM experiment. Its legacy has been to endow men and women with different and often conflicting sets of genetic interests.
It is a weary lament to lay most acts of violence and aggression parely at the feet of men. Yet the association is strong and undeniable. Women only rarely commit violent crimes, become tyrants or start wars.
The accusing finger points at the only piece of DNA which men poss and women do not: the Y-chromlosome. Ironically, although the Y-chromosome has become synonimous with male aggression, it is intrinsically unstable. Far from being vigorous and robust, this ultimate genetic symbol of male machismo is decaying at such an alarming rate that, for humans at least, the GM experiment will soon be over. Adam, it seems, is cursed. Like many species before us that have lost their males, we run the real risk of extinction.
The Y-chromosome is in a mess — a genetic ruin littered with molecular damage. Why is it such a shambles? Originally, the Y-chromosome was a perfectly respectable chromosome, just like the others, with a collection of genes doing all sorts of useful things — but its fate was sealed when it took on the mantle of deciding sex.
This probably happened in the early ancestors of the mammals, perhaps 100m years ago when they were small, insignificant creatures doing their best to avoid the ruling dynasty of the time — the dinosaurs. A mutation on one of those ancestral chromosomes suddenly, and quite by chance, enabled it to switch on the pathway to male development.
The problem is that the Y-chromosome has never been able to heal itself. Unlike X-chromsomes, which pair up and swap genes to minimise bad mutations, he Y-chromosome, which has no partner, cannot repair the damage inflicted by mutations, which keep accumulating. Like the face of the
moon, still pitted by craters from all the meteors that have ever fallen onto its surface, Y-chromosomes cannot heal their own scars. It is a dying chromosome and one day it will become extinct.
Male infertility is on the increase. An astonishing 7 of men are either infertile or sub-fertile. There are a whole host of causes but a substantial proportion, that is between 1 and 2 of all men, are infertile because of mutations on their Y-chromosomes. That is an astonishingly high figure. The human Y-chromosome is crumbling before our very eyes. There is no reason to think things will improve — quite the reverse, in fact. One by one, Y-chromosomes will disappear until eventually only one remains. When that chromosome finally succombs, men will become extinct.
But when ? By my estimate, the fertility caused by Y-chromosome decay drop to 1% of its present level within 5,000 gebnerations, wich is about 125,000 years. Not exactly the day after tomorrow - but equally, not an unimiginably long time ahead.
In June, the journal Nature announced the almost complete sequence of a human Y-chromosome, which revealed something completely unexpected. There were signs that amid the wreckage of once-active genes, the Y-chromosome is still capable of safe-guarding genes — but only by effectively having sex with itself.
Does this mean that men are now saved from extinction? Sadly not. Does the news extend men's day of reckoning? Unfortunately not.
I deliberately use "men" instead of "our species" because only men require a Y-chromosome. Of course unless something changes in theway we breed, women will vanish too and our entire species will disappear at some time in the next 100,000-200,000 years.
The questions we face boil down to this. Do we need men? Can we do without them?
There are many, of course, who would rejoice at the extinction of men. Valerie Solanas was one. She is best known as the woman who shot Andy Warhol in 1968. The previous year she published the venomous SCUM manifesto, which begins: "Life in this society being, at best, an utter bore and no aspect of society being at all relevant to women, there remains to civic-minded, responsible, thrill-seeking females only to overthrow the government, eliminate the money system, institute complete automation and destroy the male sex."
The expanded acronym of her manifesto title — the Society for Cutting Up Men — leaves us in no doubt as to Ms Solanas's preferred solution to the world's problems, but unless other arrangements are put in place, their demise will take women with them. Destroying the male sex would be a very short-lived victory. Men are still required for breeding, if nothing else. As things stand just now sperm are needed. But for how much longer?
One genetic solution that I offer is to abandon men altogether; It sounds impossible but, from the genetic point of view, very little stands in its way.
Consider what is happening when sperm meets egg. The sperm brings with it a set of nuclear chromosomes from the father which, after fertilisation, mixes in with a set of nuclear chromosomes from the mother. What is to stop the nuclear chromosomes coming not from a sperm but from another egg?
Let's think this through a little more. We know that sperm can be injected into eggs. If we can do that, there is nothing to stop the nucleus from a second egg being injected instead. That would be
very easy. But would it develop normally? At the moment the answer is no, but it is short-sighted to say that it is fundamentally impossible.
The only difference from any other birth is that the sex would be predictable. The baby is always going to be a little girl. The entire process has been accomplished without sperm, without Y-chromosomes and without men.
Importantly, the baby girls will not be clones. They are the same mixture of their parents' genes, shuffled by recombination just as thoroughly as any of today's children. They have two biological parents, not just one. Their only difference from any other child is that both parents are women.
From a genetic point of view, they are completely normal, indistinguishable from any little girls around today. In a world where men were still around, when they grew up these girls would be able
to breed in the old-fashioned way just as easily as women today. With all these advantages, I am sure that someone will try this before very long.
Lesbian couples already enlist the help of a man to donate his set of chromosomes to fertilise the eggs of one of them. At some point these couples will want to have a baby to whom both, rather than
just one of them, are parents. It is almost bound to happen and, unlike human cloning, I would have no really moral objection. Men are now on notice.
But would it catch on, and could it be an acceptable solution to the extinction of our species posed by the crumbling Y-chromosome? That is harder to say. Once men entirely disappeared, and were long forgotten, all reproduction would need to be assisted to some extent. However, if the wholesale extinction of men were to be purposefully and deliberately engineered, this Sapphic form of reproduction would have to be in place before the men were dispensed with.
There is one immediate benefit from men's extinction. In a way, Adam's curse is permanently lifted. Sexual selection disappears for the simplest of reasons — there are no longer two sexes. Sperm no longer fight sperm for access eggs. There are no sperm to do battle, no chromosomes to enslave the feminine.
The destructive spiral of greed and ambition fuelled by sexual selection diminishes. The world rio longer reverberates to the sound of men's clashing antlers and the grim repercussions of conflict.
But let's look at the alternatives. Extinctions happen all the time and I suspect that a good many species have already fallen victim to the process of chromosome decay.
Some, however, have found a way around their death sentence. One strategy is to recruit genes on other chromosomes to take over the job of male development.
It might take only a small mutation to convert a gene on another chromosome so that it becomes capable of duplicating the job of one of the endangered Y-chromosome genes. This way, when the gene was eventually battered to death on the Y-chromosome, its job was already being done elsewhere and its disappearance from the Y no longer mattered.
It is a race against time. Can a species get the genes it needs off the Y-chromosomes, or recreate them elsewhere, before it goes belly up? Always the last gene to go will be the Y-chromosome's sex master switch itself, the SRY (Sex-determining Region on the Y-chromosome). We know it is capable of jumping ship and smuggling itself onto another chromosome.

The mole vole Y- chromosome has now completely disappeared. The mole vole is now safe from Y-chromosome-driven extinction, the only mammal species known to have succeeded in getting itself out of danger. For the mole vole, the problem has been shelved for tens of millions of years.
For us and all other mammals who still have to rely on a Y-chromosome to make males, the danger is much more immediate.
Many men have overcome their infertility with the help of a fertility treatment called ICSI, which stands for intracytoplasmic sperm injection. Introduced in Belgium in 1992, ICSI is an extension of the well-known procedure of in vitro fertilisation where an egg and sperm are mixed in a test tube and the embryo which grows from the fertilised egg is reimplanted in the mother's womb. That technique
introduced to the world by the birth of Louise Brown in 1978, has since helped an estimated 700,000 couples to have their own children.

With ICSI, the sperm do not have to be capable of fertilising an egg on their own, as in straightforward in vitro fertilisation. They get help. Even. a completely immobile sperm can reach its destination. It is simply injected directly into the egg with a fine needle. Once inside, its handicap no longer matters and fertilisation goes ahead as normal. Then, just as in run-of-the-mill IVF, the embryo is implanted back into the mother.
What could be simpler? Infertility cured. Or is it? The danger is this. If the man's infertility is caused by a damaged Y-chromosome, then ICSI will hand this Y-chromosome on to all his sons — who will themselves be infertile for exactly the same reason as their father. If that happens, they are going to need ICSI to have children too. We have merely handed down the problem to the next generation.
Although ICSI will not prevent the extinction of men, it is at least a technique which we know works. The other remedies that spring to mind have yet to be proved effective, but if men are to be retained they are at least worth considering. For instance, what would happen if we deliberately abandoned the Y-chromosome and switched the necessary genes to the other chromosomes where they would be safe?
In other words, if we pre-empted the demise of the Y-chromosome and deliberately engineered the solution so fortuitously arrived at by the mole vole? The human Y-chromosome could be left to decay — it cannot be saved — but men would be reprieved.
But could this be made to work?
It will not be long before we know all the genes that are present and necessary on today's Y-chromosome to make a man in full working order. We know most of them already — including SRY, of course, and the few genes that help to make active sperm.
Even with today's comparatively primitive genetic engineering technology, once they are all known, it will be easy to cut them out of the wreckage of the Y-chromosome and assemble them together in a compact genetic pack, age. Or they could be made from scratch, even with present-day DNA synthesis instruments.
From there, it would be a relatively straightforward task to insert the package into another chromosome, and the chances are it would work straight away. A fertilised mouse egg destined to become female has been successfully diverted to at least superficial masculinity by the injection of the mouse equivalent of SRY. Sure, it was infertile; but if the egg had been injected with the complete package of male genes, the mouse would have been both male and fertile.
A fertilised human egg which would otherwise develop into a girl would, given this treatment, grow into a perfectly healthy man indistinguishable from any other, until you looked at his chromosomes. He would have two X-chromosomes; but instead of being infertile like XX males today, this man would have all the necessary sperm genes.
But what about his own children? No immediate problem there either. Assuming that the package of male genes had landed safely on one chromosome, this new-age Adonis would be able to have sons and daughters in equal proportion, their sexual destinies decided only by whether they received from him a sperm carrying the repackaged chromosome with the added genes (for sons) or an original (for daughters.) The prospects for the Adonis chromosome are excellent. It will reprieve men from the brink of extinction and guarantee them a future for several million years.

Edited extracts from Adam's Curse, by Bryan Sykes, professor of human genetics at Oxford University, published by Bantam Press on September 4, £18.99.