Viewed purely from an evolutionary standpoint, there is only one valid biological lifestyle for the human male and that is heterosexual. Like all higher forms of life, the human species relies on sexual reproduction to avoid extinction. If a man does not allow his sperm to fertilise an egg at least once during his lifetime he has no chance of passing on his genes to the next generation, and the genetic line, hundreds of millions of years long, that led up to his appearance on earth is terminated.

The question is why a certain, small percentage of adult human males, with or without the approval of society at large, find members of their own gender attractive as sexual partners. Evolution has gone to a great deal of trouble to ensure that it is the opposite sex that is erotically appealing, so how can it be that so many men have somehow switched off these basic responses?

When questioned about the onset of their same-sex interest, many homosexuals say that from boyhood onwards they felt a strong attraction to other males, and never felt drawn to young females. This sets them apart from young boys who often play homosexual games with their male friends, but who pass on to a new phase when their interest switches to girls. For the lifelong homosexuals, this switch never happens. To understand why, it is important to look at the typical sequence of events in the first 20 years of the life of the human male.

For the first few years toddlers make no distinction between male and female friends. Then, when they reach the age of 4 or 5 the sexes suddenly draw apart. For a small boy, the little girls who were his close friends only a few weeks before must now be avoided. Now he plays only with other boys.

He becomes part of a group and the boys hang out together. This phase will last about ten years, during which time he will be going through an intensive educational period, programming the amazing computer inside his skull. Even if boys and girls go to school together during this phase, they will separate from one another socially. Indeed, despite modern educational theory, mixing boys and girls during this phase of growth is of little advantage. It may even be distracting.

This ten-year learning phase is something that other primates do not have. They reach sexual maturity in about half the time but, of course, they have smaller brains and far less to learn. The boys-together schooling phase is something special that has been added to the human life cycle. At the end of it, in the early teens, the bodies of both boys and girls start to flood with sex hormones and now, suddenly, the opposite sex is of interest again. During the ten-year stand-off they have become distant objects, often disliked. Now they are a new shape and have new features, as the secondary sexual characters begin to develop.

So the stand-off period has made the opposite sex into a novelty, a mystery, something to be explored. (For boys, this reaction does not apply to their sisters, because as siblings they have been pushed close together by family constraints, a fact that helps to avoid incest.) At this point boy-meets-girl is a theme that dominates the lives of teenagers, and intense sexual exploration is not far away.

There will be a brief period when there is a conflict between the old, all-boy gang and the new interest in girls. Each boy will have to report back to his chums to tell them how he has progressed with a particular girl, until, one day, there is a stubborn refusal to give them any details, and they know instantly that they have lost one of their group.

Returning now to the boys who do not reach the teenage heterosexual phase, they get stuck in the stand-off phase, and stay there for the rest of their lives. They cannot understand why young boys, who were playing sex games with them only a few months before, are now only interested in chasing girls. The all-boy phase seems perfect and when sexual maturity arrives, they feel no urge to abandon their all-male social existence. Their sex hormones activate them erotically, but their focus of interest is still masculine. This is how the lifelong homosexual male starts his sexual journey, but why does it happen to just a few boys, while the majority move easily to the heterosexual phase?

The answer seems to be that it is the unique addition of such a lengthy ten-year learning phase in our species that causes the problem. During that phase, male bonding is intense and male-to-male attachment is powerful. It takes a massive jolt from the sex hormones at puberty to break down the boy-to-boy loyalties, and if there are any special social factors adding their weight at this point, the break can be thwarted.

These factors can be of several kinds. A boy who has especially unpleasant experiences with girls during the stand-off phase may find that, even flooded with sex hormones, he cannot switch into the state where he finds them appealing. Or he may have found the boyish sex games that are so common in the stand-off phase to be particularly exciting and this may have fixated him on other males as sexual companions. For him it is impossible to make the switch because he cannot bear to leave behind what he had before.

There are many other social factors that impinge upon the prepubertal male and imprint upon him powerful attachments. The reason it happens to him and not to young monkeys is that other species lack this vital stand-off phase and are never put in this position of key switch from boys-together to boy-plus-girl.

In his study of what he calls The Eternal Child, zoologist Clive Bromhall says this extended childhood is part of a general infantilising of the human species, a process he sees as the basis of our evolutionary success story. As a way of maximising our human playfulness and curiosity, evolution has made us more and more childlike over the past million years or so. While this has made us more inventive and given us the technology that has made us great, it has also had certain side effects. To explain these, Bromhall suggests that there are four types of human male.

There is the Alphatype, like an alpha male ape, ruthless, determined, ambitious, strong and intolerant. Then there is the Bureautype, still concerned with high status, but much more cooperative, making him the perfect business partner. Thirdly there is the Neo-type, more childlike, the exuberant, fun-loving family man.And finally there is the Ultra-type, imaginative, insecure, and unable to move on past the all-boy phase of childhood.

Bromhall sees this last type, to which homosexual males belong, as a byproduct of the increasingly infantile condition of our species. In other words, when evolution took the human species down the road of increasingly playful, innovative behaviour as a new survival device, the process was not too precise. The ideal outcome would have been to create a species made up of a balanced mixture of reliable organisers, the Bureautypes, and creative fun-lovers, the Neotypes. But this shift was not fully achieved. At one extreme there remained a few of the old-style Alphatypes, the macho toughs, good in a fight but poor cooperators; and at the other end of the scale a few of the new-style Ultratypes, so advanced in this new evolutionary direction that they got stuck at the boy-group stage.

If, as a result, the Ultratypes accidentally became “reproductively challenged” they also became unusually imaginative and intellectually inquisitive. Bromhall reports that their academic achievements are well above average. A male homosexual is six times as likely to gain a college education and 16 times as likely to have a PhD as males in general.

But what of the future? People deserve to be treated as individuals rather than as members of a group that they did not join but which was thrust upon them. Isolating homosexuals as though they are members of some exclusive club does them no favours. It encourages bigots to attack them, which makes about as much sense as outlawing left-handers or redheads.

— © Desmond Morris 2008 Extracted from The Naked Man: A Study of the Male Body, by Desmond Morris, published by Jonathan Cape on January 3, 2008. RRP £18.99, available from Times BooksFirst for £17.09, free p&p: 0870 1608080, timesonline.co.uk/booksfirst

In defence of the ‘redundant male’

In recent times there has been much talk about the “Redundant Male”, the suggestion being that with new, artificial fertilisation techniques men will soon become obsolete. This theory first became popular in the 1970s when leaders of the feminist movement announced that males were not worth the trouble in the bedroom. However, even if men were not necessary for sexual pleasure, there was still the tricky problem of how to procreate the next generation of feminists. A few champion ejaculators would have to be kept for this purpose, with sperm samples being ordered whenever they were needed.

Since then, advances in reproductive technology have been made that suggest that one day, in the not too distant future, even sperm will not be necessary. Women will be able to have their eggs fertilised in the laboratory without any male element being involved, and then have them reinserted in the uterus to grow into a new generation of females.

Lesbian pairs will be formed to create a new type of family unit with baby girls being reared in a male-free world.

According to this ideal, the absence of males will mean an end to warfare, testosterone-fuelled violence, aggressive sports, football hooligans, political extremists, rapists, religious terrorists and all the other destructive aspects of the masculine world. In its place will be the caring, sharing, gentler, more intelligent world of the human female.

Quiet common sense will replace savage conflicts of honour, and life will become a warm, safe, friendly experience rather than a cruel, anxiety-ridden ordeal.

How all the existing men would be disposed of is not clear. Perhaps they are just ignored and allowed to grow old until the male gender slowly fades away. Eventually they will be no more than a distant memory, and a testosterone-free planet will rotate to the sound of female laughter.

On a serious note, in addition to ridding the world of the destructive elements in the masculine psyche, this extreme scenario would also remove all the constructive elements. There would be far fewer major inventions – they would be considered too risky. There would be far fewer single-minded, long-term projects – too time-consuming when set against the demands of family and daily social life.

If women have always been more sensible than men, men have always been more playful than women. And it is this adult playfulness that has given the human species many of its greatest achievements.

If we allowed the champion of all things male to offer his riposte to the feminist position, he would probably say: Yes, there may have been great female artists, scientists, politicians, religious leaders, philosophers, inventors, engineers and architects. But for every one of them there have been a hundred men, possibly a thousand. Greatness seems to demand the sort of stubborn perversity that is a predominantly male quality.

It has often been argued that this has been a matter of opportunity – that women were not allowed to develop their true potential. But in practical terms this simply means that women were not great enough to demand that their greatness be recognised. Greatness has to be achieved, not merely postulated, and it is the men who have been driven on by their genetically installed ambitions actually to take the great steps necessary to build our towering civilisations.

Both these extreme views are exaggerations and represent the enormous waste of energy that has gone into the so-called battle of the sexes. The truth is that the human male and the human female make a perfect evolutionary team. They are different in important ways that have evolved over hundreds of thousands of years to refine the division of labour in the human tribe, but at the same time are equal in importance. Different but equal, that is the key.

The male brain has become specialised in single-minded determination, the female brain at multitasking. The male has become specialised in planning, innovating, risk-t-aking, spatial problem-solving and muscular expression. The female has become specialised in verbal fluency, and with better developed senses of hearing, smell and touch, and a greater resistance to disease.

— DESMOND MORRIS

You’re so wrong, Prof

What garbage. I, and many of my friends, didn’t “pull away” from boys or girls at any age. We didn’t do “single sex gangs”. I had a conventional upbringing and, how dull, never experienced “sex games” with other boys. My sexuality is not “infantile”, but as adult, evolved (and complex) as any heterosexual’s. Apparently, being gay, I am a glamorous-sounding “Ultratype”: “imaginative (that’s OK),” but also “insecure and unable to move on past the all-boy phase of childhood”. But what if you never had an “all-boy phase of childhood”? What if you are secure in your sexual identity?

In my experience most boys from all-boy environments turn out straight. Growing up gay in an all-male environment is homo-hell, not paradise. Professor Morris is avowedly unhomophobic and argues against “isolating homosexuals as though they are members of some exclusive club”, while doing precisely that. Gay men come in all shapes, sizes and natures. We are warriors. We are hairdressers. (And sometimes we are warrior-hairdressers.) The men I know, gay and straight, encompass all four of Professor Morris’s “types”.

The Prof has lovely things to say about how successful and generally brilliant gays are: if it’s true, then it’s down to making their way, with grit and wit, in a world that seeks to dumbly classify and pigeonhole them.

— TIM TEEMAN