The answer, according to the experts, is to become ill; depression in its various manifestations is a growing concern. Stress-causing situations involving unemployment and, at the other extreme, overwork in an insecure job environment are intensified by the failure of society to enable men to immerse themselves emotionally and practically in fatherhood and childcare.
According to psychiatrist Dr Sebastian Kraemer, based at the Whittington Hospital and the Tavistock Clinic in London, the ensuing conflict - between new expectations of being a caring and fulfilled parent and the reality of a society that indicates that you do not really belong in the home - contributes to a feeling of powerlessness and confusion and, in turn, to emotional and physical ill-health.
"The advance of women, together with unemployment and lack of job security, have taken power away from men as never before," says Dr Kraemer. "There will increasingly be work for women because they can do most jobs as well as men, they are more adaptable and they still accept low pay as an alternative to no work at all. But that leaves many men walking the streets, unless they can find some other role."
Seventy-five per cent of young women feel able to rear their children without the necessity of a male breadwinner, according to the Demos report, Freedom's Children, published last September. This survey of attitudes among the nation's 18- to 34-year-olds also reveals that one in five women now earns more than her male partner (compared with one in 15 a decade ago), and that young women in social classes C2, D and E are more committed to achieving success than their male counterparts. In the professions also, the prospects for female achievement have improved massively in recent years. "The typical female professional is now young, while the typical male professional is old," note the report's authors, Helen Wilkinson and Geoff Mulgan.
But it is not simply the lingering pressure to be the breadwinner in the boardroom - it must be remembered that women executives are still thin on the ground - that is causing men's anxiety, according to psychosexual therapist Joyce Keith. It is also the myths surrounding male sexual behaviour and the outmoded pressure to perform in the bedroom. She is concerned particularly with the ideas that real men are always ready for sex, that they must take charge of and orchestrate love-making, and that in this sphere of activity, as in other aspects of life, performance is all that counts.
You only have to look at the cover lines on this month's men's magazines to see how the potency myth continues to be fuelled. "The art of seduction - a Casanova's cribsheet" (GQ), "Wild! Ancient sex tips for the modern man" (February's Maxim), "Last longer in bed" (Men's Health). Far from keeping the home fires burning, urging, some would say pressurising men to perform well in bed in a supposed age of sexual equality and New Man- ism is a major cause of needless disharmony in relationships, according to Joyce Keith.
The pressure on women to be both good, sexy lovers and good, practical mothers has, of course, existed for decades. Nevertheless, the number of couples coming to Relate clinics with difficulties attributed to lack of sexual desire in the male partner has almost doubled over the past few years. This lack of sex drive is distinct from the inability to attain and maintain an erection, which is the medical definition of impotence (see box). But it can be equally destructive in a relationship.
Joyce Keith describes a situation frequently encountered in the Surrey commuter belt where she works. A man comes home after a full working day, lengthened by tiresome travelling. Not unnaturally, he wants to have time with the children, feeding and bathing them, putting them to bed. "And then on top of that there is the expectation that he will also perform sexually," she says. "He may well find that he cannot." If the problem is not discussed and the myth of the ever-ready male is not confronted, it can become the source of anxiety, bitterness and low self-esteem which feeds back into the relationship.
"You don't feel a man. You don't feel complete. And I gave up even trying. I don't want to start anything now because I know I'll fail," is how one of Joyce Keith's clients puts it. His wife had an equally familar problem: being unable to accept that lack of sex did not mean lack of feeling for her. "Part of me knew that he cared, but another part thought that if he really loved me he would be able to have an erection," she said.
"The body only responds in a sexually positive way under certain conditions," Joyce Keith says. "The arousal system is extremely sensitive to certain feelings, particularly anxieties about performance. The way to get rid of those anxieties, she believes, is to unlearn the stereotypical expectations of manhood and sexual performance learnt in the playground.
Mike Luck, a contributor to the recent Community Health UK document on the crisis in men's health, laments the lack of genuine information available during his formative years. At that stage, everything was concentrated on the man's own supposedly limitless sex drive: the partner's needs did not come into it. "I can't remember ever having a sensible conversation about this with anyone - father, elder brother, friends or teachers," he recalls. "Only recently have I had some sexual experiences which seem to be uncomplicated, unanxious, about mutual exploration and delight."
For all those men unable to cope with perceived expectations regarding earning power and sexual power, there are many others who feel that, in an age where there is a greater openness about sex, where roles are fluid and where counselling is there for the taking, there really could not be a better time to be a man.
"You can be who you want to be today," says one 30-year-old self-employed textile designer. "It is acceptable to be high-earning and ambitious, to be a caring father, or to be laddish. It is easier to be a man now - men are not as uptight and worried about social and financial status, as my father's generation was. And as for sex, it is based on mutual desire and understanding. I don't see that I have to be the one always to initiate sex."
For millennia, most cultures have simply assumed that the world was and always would be organised around men. Now this myth of power and authority has all but disappeared. "If there is no God-given way for men to behave, they have to work it out for themselves." says Dr Kraemer. "One option, which many take without real thought, is to have children."
But even then, men are still inclined to feel that their jobs define them and give them value in the world. "Without this identity, men are much more likely to get ill, mentally and physically," says Dr Kraemer. "And the damaging effect of unemployment may extend across the generations. One of the clues to the riddle of increasing suicide rates in young men may be that even if they themselves have work or study to occupy them, they are the sons of men who do not, and so are deprived of a vital role model."
There is a world of difference between being the source of sperm and being a true father. What Dr Kraemer has in mind as a suitable new role for men is not the old concept of fatherhood as the source of family discipline, it is not the relatively recent idea of the father as rough-and-tumble playmate, nor even the New-Man role of nappy changer. It is that of the father taking a fair share of a lifetime's loving care.
"What is so pathetic about the plight of many young men is that they want to be loving towards their children, but don't dare," he says. "There is a taboo on tenderness due in part to the intensity of emotion created by being in close contact with your own baby and in part to the powerful social pressure on men not to behave like women. For this reason, there is an almost confessional aspect when men admit to each other how much child care they undertake."
Surviving myths about what it means to be a powerful male stand in the way of men finding a new role in fatherhood. For men in work, practical difficulties also contribute. Within the European Union, Britain has the highest rates of overtime worked by men and among the poorest provision of paternity leave.
Last year's Demos report on attitudes among today's young adults demonstrates that support for a gender-based division of responsibility between home and work has all but disappeared. In recognition of this, the report's authors call for a "new parentalism" focusing on government allowances for children and giving greater rights to child-care leave irrespective of sex.
The most important qualities in a good father are not significantly different from those in a good mother. This does not mean that men and women have to be the same. On the contrary, Dr Kraemer argues, the benefit of having two parents involved is precisely that they are different people, and of different sexes, and with complementary attributes.
But the new fatherhood must mean some acknowledgement of weakness in the tough facade men are still supposed to present to the world. In the words of Leonard Cohen quoted recently by the Men's Health Awareness Project, "There is a crack in everything; that's how the light gets in."
The alternative view
DAVID McDONALD, 28, merchant banker
Most men of my generation were brought up and modelled themselves on their dads who, in today's terms, are real sexists. We are caught in the middle. I would have no problems giving up my job to look after the kids. I love kids dearly. If you ask any bloke, even those who work 14-hour days, they say the whole point of it is the kids.
And I don't have any problem working with women who earn more than me. As long as they are good at the job, then they are earning their money and it's fine with me.
DAVID IWAN, 29, solicitor
I don't have any worries about my masculinity, certainly not in the way that straight men do. They don't generally experience a lifestyle change big enough to make them question their very conventional view of the world - marriage, kids, friends, career. As a gay man, on the other hand, I've been forced to recognise and overcome the fact that I belong to a stigmatised section of society.
I have a female boss who is three years older than me and earns about four times more. This doesn't threaten my masculinity, but I can remember a time in my painful teens when it would have done - the pressure to do the right thing in order to be the type of man my parents had in mind was very strong. They wanted a married professional man with children, dogs and a Volvo.
Interviews by Nick Walker
Everything you ever needed to know about impotence (but were too embarrassed to ask)
is defined as the inability to attain and sustain an erection sufficient for sexual intercourse
is common, affecting more than one man in 10
is treatable using techniques that range from psychotherapy to surgery, drugs to prostheses but it is estimated that fewer than 10 per cent of men affected are currently receiving treatment
occasionally afflicts most men, commonly due to fatigue, stress or excess alcohol
is due in around 70 per cent of all longer-term cases to a physical cause. This may be a disease such as diabetes, high blood pressure or vascular problems, nerve damage due to trauma or surgery, or the side- effect of drugs such as those used to treat hypertension and depression.
Men who are impotent are often reluctant to consult their doctors out of sheer embarrassment. A new booklet, Regaining Potency, has been published by the medical journalist Oliver Gillie. It explains the possible causes and describes in detail the medical, physical and psychological treatments available. Regaining Potency is available from Self-Help Direct, PO Box 9035, London N12 8ED, price pounds 6.75.
The Impotence Association provides a confidential helpline for those with erectile dysfunction who are seeking advice and information about available local services. All the specialists listed work for the NHS but some may also have private practices. Tel 0181-767 7791.