THE ageing of the American population continues to make headlines. Predictions that by the year 2050, life expectancy will be 100, compared with today's 73, and that median age will be 53, as St the current 31, are greeted with dismay or optimism, depending on the analyst's projections. All agree, however, that the ratio of elderly dependants to middle aged workers in 2050 will be four times the present one.
But the greying of American society is just one part of a far bigger story. There is a revolution throughout the life cycle. Early puberty and prolonged adolescence, for example, are changing our definitions of maturity and altering society in a more profound way than pension funds ever could. Within one short generation, the configuration of the human span has been fundamentally altered. Put simply, more Americans are leaving childhood earlier but are taking longer to grow up.
If children have become more like adults, adults have become more like young people," observes Joseph Kett, author of Rites of Passage Adolescence in America. Prof Kett may sound like just another old fogey, who sees things falling apart when he notices policemen getting younger, but statistics confirm his observation.
The age at which girls begin to menstruate, for instance, has been falling steadily throughout the developed world. In 1840, the average age for the onset of menstruation in England was about 17 years, according to Dr John Tanner, a University of London paediatrician and an expert on the subject. By 1900, in countries with improved health nutrition, it had dropped to 15 years.
Today the average age girls start menstruating in countries like the US ranges between 11 and 13 years the age at which an increasing number of girls, particularly in America's inner cities, will also become mothers. Since 1992, more than two million babies were born to teenagers in the US, the average age of those mothers falling with each year.
Earlier puberty is usually viewed as a predictable side effect of economic development improved health and nutrition causes earlier menstruation and pregnancy is a likely consequence. But a controversial theory now suggests that something more fundamental is taking place at this critical stage of the life cycle.
Young mothers may be responding to a pattern in human evolution that induces people growing up in extremely stressful circumstances to bear children early and often. Accept that view and early puberty becomes chiefly a response to disrupted households, divorcing parents or absent fathers.
"It's not a conscious, deliberate strategy," Dr Jay Belsky, a psychologist at Pennsylvania State University, recently explained to the New York Times, "it's a biological response. In stressful conditions, evolution has primed you to pursue a quantity rather than a quality reproductive strategy. Earlier puberty is part of this plan."
CRITICS of Prof Belsky's evolutionary interpretation of teen pregnancy stress other plausible explanations girls from troubled families receive less parental supervision, have dim job prospects and little sense of a worthwhile future. They are also likely to have mothers who menstruated at an early age a critical factor in the daughter's development and who consequently married early themselves. "And those who marry earliest tend to have made the worst marital choices," argues Dr Terrie Moffitt, a University of Wisconsin psychologist.
Experts may disagree on the role of hardship in a girl's physical development but all regard prolonged stress as a destroyer of childhood.
"There are no children here," LaJoe Rivers, a mother of two boys, told writer Alex Kotlowitz when he proposed a book about the children in her poor Chicago neighbourhood. A 1992 survey of children aged six to 10 years in Washington DC revealed that more than 90 per cent had witnessed severe violence, over 40 per cent had sheen dead bodies, 70 per cent had seen weapons being used and 100 per cent had friends or family members who had been killed. Every day in the US, 135,000 children bring guns to school.
"Some inner city children exhibit post traumatic stress symptoms similar to those that plague many Vietnam combat veterans," says Marian Wright Edelman, president of the Children's Defence Fund.
Heightened cholesterol levels, ulcers, allergic reactions, migraines and other anxiety related ailments are increasingly reported among children in affluent as well as deprived households, concludes David Elkind, author of The Hurried Child Growing Up Too Fast, Too Soon.
If childhood is ending earlier, adolescence is lasting longer indefinitely according to Robert Bly, who became the men's movement guru with Iron John and whose latest book, The Sibling Society, condemns what he sees as a culture that perpetuates adolescence.
"People don't bother to grow up," Bly writes, "and we are all fish swimming in a tank of half adults." Drawing on myth, religion, fairy tales and even science for evidence of this decline, Bly asserts that instead of maturing with the guidance of older mentors, young adults refer only to their peers worldwide "because only people one's own age are worth listening to".
WHERE Gail Sheehy in her 1995 book New Passages saw an exciting phenomenon and a new frontier true adulthood being postponed until the 30s or even 40s, middle age pushed into the 50s, 45 as the threshold of "second adulthood" Robert Bly sees a crisis. The paternal society, now discredited, has been replaced by one in which impulse rules "where parents regress to become more like children and the children, through abandonment, are forced to become adults too soon and never quite make it," he contends.
In a world where 40 year old women are considering their first pregnancy, where 55 year old women can have egg donor babies and 70 year old men can turn the clock back by 20 years thanks to a human growth hormone, Sheehy contends that "on the new human frontier . . . we are all casting about for accurate maps and finding the maps woefully outdated."
On the contrary, says Bly, the very idea of needing maps for direction, inspiration or comfort is outdated in an adolescent world and the traditional pathfinder the father has become either invisible or irrelevant. Citing a poll that found the average American father talking to his child for just 10 minutes a day, Bly argues that television "the thalidomide of the 1990s" has replaced that inter generational conversation with a self referential monologue "teaching that no one is superior to anyone else and high culture is to be destroyed".
Cultural and spiritual decline is impossible to quantify, however, and other commentators are more alarmed by the measurable consequences of the absent father in the sibling society.
"Without a father for a role model, many boys learn about relationships from their peers on the street," Newsweek reporter Michelle Ingrassia explains. "In the inner city that often means gangs and the message they're selling is that women are whores and hand maidens, not equals."
The extended family, which traditionally shouldered the child rearing burden, is also near extinction. Grandmothers are getting younger and are more likely to be working.
"A 32 year old grandmother isn't necessarily eager, or able, to raise a grandchild," Ingrassia points out. "And, after generations of no fathers, there are no grandfathers either." As Gail Sheehy describes it, the ability to live three adult lives instead of just one may sound like a miracle. More sober evaluations reveal, however, that like most bargains, this one has its hidden costs.