(FORTUNE Magazine) – NOTICED many pregnant women in your office the past few years? Lots of strollers in the local park? It's what number crunchers call anecdotal evidence -- you see something that looks like a trend, yet can't ''prove'' it. Indeed, conventional wisdom, based on Census Bureau forecasts, holds that birthrates will decline. Now the numbers are starting to document what the eye can see. Babies are back, the rise in the percentage of women entering the labor force has stopped growing, and younger women seem more interested in starting families earlier than their older sisters. The signs all point to a bona fide baby boomlet. Yes, the 1990s really are going to be different. If the demographers descrying the baby trend are right -- and they put up powerful arguments -- ten million more small Americans than foreseen by the Census Bureau will be around by the year 2000. That's bad news for those who sell sports cars, run fancy resorts, or operate haute cuisine restaurants: Tomorrow's homebound consumers will have fewer discretionary dollars available for pricey pleasures. For makers of kids' clothes, toys, and the like, there will be opportunities aplenty. Census Bureau population projections are enormously influential among business and government planners. In its most recent estimate, published in 1989, the bureau predicted 3.7 million births in 1990. Actual result: 4.2 million (see chart), the most since the late baby-boom year of 1961, when 4.3 million children entered the world. And 1989 was pretty boomish too, with four million new citizens. How could the agency have underestimated so badly when it knew how many American women were in their childbearing years? It looks at something called the total fertility rate -- the number of babies a woman would have in her lifetime, given the current year's fertility patterns across age groups. Through most of the 1980s the rate was 1.8, which the bureau used in its projections. On its side: the continuing expansion of women's job opportunities, incomes, aspirations, and independence. What modern woman would want to be tied down by bottles and diapers when she could be doing leveraged buyouts? Quite a few, it turned out. In 1990 the fertility rate reached 2.1, and that seemingly small change resulted in the half million extra births. Especially notable: a sharp rise in the birthrate among college-educated managers and professionals over 30, according to biennial census surveys. These are the women who delayed childbearing to pursue careers and are now bent on catching up. Though much attention has been paid to the soaring number of out-of- wedlock births, the more important news for business is in the number of births to married women, which began to rise in 1988 after sinking for two decades. Married couples have both the will and the wallet to treat their babies to the best. The question now for demographers and marketers: Will the baby buggy soon come to a screeching halt when women who delayed childbearing finish beating the biological clock? After all, the typical baby-boomer today is thirtysomething. You might well expect that the educated, ambitious American woman will quickly revert to her ways of the 1970s and early 1980s, and either postpone children or have a baby and go back to work. It's still a staple of establishment thinking that young women will choose to have few children. Not so, asserts Richard Easterlin, demographer at the University of Southern California. Easterlin expects that the fertility rate will rise markedly this decade to as high as 2.7 children per woman -- a level the U.S. hasn't seen for a quarter-century. Births fell in 1991, but only because of the recession, he says. Even so, they tallied around four million, vs. the census projection of 3.7 million. Easterlin has made a career of challenging conventional wisdom. During the 1970s he was forecasting an upsurge in the 1990s. He made that call during the heyday of the Limits to Growth and Zero Population Growth movements, when it was widely agreed that the fertility rate would head down as it had for 100 years, interrupted only by the anomalous baby boom. | What caught Easterlin's eye was not the long-term downward trend but the tremendous swing in birthrates during past decades. Something fundamental had to be at work, he figured -- a factor that would influence future cycles. The something turned out to be a couple's income, mostly the husband's, relative to the couple's material aspirations. Those aspirations, in turn, are largely determined by their parents' incomes. The higher a couple's income relative to their aspirations, Easterlin found, the higher the fertility rate. And income is heavily influenced by the size of the couple's generation: If there are lots of people, they crowd into the labor force, pushing wages down compared with those of their parents' generation. That's what happened to the baby-boomers, and it is why their fertility rate fell below replacement rates in the 1970s and much of the 1980s. Hold on. Didn't the boomers have it good, weren't they big spenders, didn't they unleash yuppies on society? Sure enough. Their parents' prosperity gave them big aspirations for consuming. But since there were so many of them, they had to pay for their pleasures by putting off marriage and children. Boomer women thronged to the career ladder and climbed with tenacity. The baby-busters, those born roughly between the mid-Sixties and the early Eighties, are more likely to enjoy good wages because of their smaller numbers. Despite modest economic growth and continuing corporate restructuring, incomes will continue to rise unless the economy of the coming decade turns out far grimmer than seems likely. The gains should be strong enough to push the total fertility rate well above where it is now -- especially since several years of weak growth and recession have diminished so many aspirations. Other researchers support Easterlin's thesis. Diane Macunovich, a professor at Williams College, has calculated that wages of young workers relative to their parents' wages five years earlier -- when the youngsters were forming expectations -- began to rise in 1985. That foreshadowed higher fertility in the late 1980s, with the rate for 20- to 24-year-olds rising to 115.4 births per thousand in 1989 (the latest data available) from 107.3 in 1984. Comparing the number of younger vs. older workers, Macunovich projects continued increases in relative wages for those in their late teens and early 20s through the year 2000, implying higher fertility rates. Now look at what's been happening to the birthrate among women ages 25 to ! 29, who were born as the baby boom wound down: Births hit 116.6 per thousand in 1989, compared with 108.3 in 1984. Why? These women are in a less crowded marketplace than their older sisters. And many who've been hearing about how draining it is to have a newborn at 35 or 40 seem to be advancing their plans. THEN there's the development that probably seems incredible to anyone who's come of age since the mid-1960s. The rise in the percentage of women entering the labor force has stopped. Year in and year out, through recession and expansion, the female labor force participation rate grew from 37.7% in 1960 to over 57% in 1989. But there it has stuck ever since, another example of conventional wisdom confounded. In its most recent long-term forecast, the U.S. Bureau of Labor Statistics predicts the rate will hit 60.1% in 1995 and 62% in 2000. Not likely, says the Easterlin school, because as relative wages of husbands improve in the 1990s, women will work less. Now he's gone too far, you say. Though Easterlin cites survey data to buttress his point, Macunovich's students at Williams, an elite school that attracts careerists of both sexes, were doubtful. So last year they polled their fellows on childbearing attitudes. They found that 87% of female and 95% of male students expected to have two or more children. Women said they intended to cut weekly work hours from 44 to 18 while taking care of young children. There's other corroboration. Parenting magazine found that 57% of its readers in 1990 -- average age, 30 -- planned to have more children, up from 44% in 1987. The percent of full-time homemakers rose to 30% from 26%. Yankelovich Clancy Shulman, a Westport, Connecticut, market research firm, found that 28% of working women in 1990 wanted to quit their jobs to put more energy into being mothers and homemakers -- nearly double the share in 1981. ''In practical terms, most women will still have to work because they need the money, but our research shows they are not as committed to their careers, and so will work fewer hours, travel less, and take less work home,'' says YCS senior vice president Susan Hayward. ''The job must share time with husbands and kids.'' MARKETERS should heed the implications. The U.S. Department of Agriculture calculates that a middle-income American family will spend $120,000 in 1990 dollars to raise a child to age 17, before paying for college. American Baby magazine projects that, based on trends that began in the 1980s, an increasing number of couples will have a second and third child in the next few years. Larger families spend less per child, but the total dollars build into a mountain. The USDA also found that though 59% of wives without children work full time, the proportion drops to 31% for wives with a baby and to 18% when other children are also present. Some moms switch to part-time jobs, but after-tax family income still falls 10% to 20% on average. Outlays drop only 6%, but what a difference in the mix. Feeling as if they're spending the entire GDP on diapers, formula, pediatricians, and babysitters, parents won't be much in the mood to shell out $100 for a Broadway show, plus dinner and parking. Such shifts could upset business plans seemingly based on obvious truths. For example, a marketing report from McKinsey & Co. expresses the widely held view that eating out will claim a significantly greater share of consumer food dollars by the year 2000. The USDA, however, finds that after baby's arrival, such spending plunges 44% while food-at-home outlays rise 29%. Cost-conscious families may think twice about even fast food -- sales growth has slowed markedly in recent years. If you've got any doubt that babies are in and are affecting consumer behavior, just check out your favorite romance novel emporium, where you'll find the likes of Baby Aboard. ''Carson was in the mood for love, all right -- but were Lisa's enticing ways enough to lure him to marriage . . . and a baby carriage?'' Hint: On the last page, Carson closes his eyes as he holds her, saying: ''A family. Yes. That's a promise.''

CHART: NOT AVAILABLE CREDIT: FORTUNE CHART/SOURCES: CENSUS BUREAU; R. EASTERLIN, USC; DENNIS AHLBURG, UNIV. MINN. CAPTION: BET ON THE BOOMLET The Census Bureau is far short of the mark, says demographer Easterlin.