Delayed Childbearing

Last fall, in San Antonio, Texas, at a session for infertility counselors held in conjunction with the annual meeting of the American Fertility Society, Dorothy Mitchell-Leef strode to the microphone during a question-and-answer period and presented a manifesto of sorts. Mitchell-Leef, a prominent reproductive endocrinologist, declared that in effect women have been sold a bill of goods.

For years physicians have said little as women have chosen to put off having children until their mid-thirties, their late thirties, their forties. The time had come, Mitchell-Leef believed, for a message to be delivered. She told the participants—mostly psychiatrists, psychologists, and clinical social workers—that women should be advised to consider having children earlier in their lives rather than later. In response her audience, most of whom had witnessed the anxiety and grief experienced by older women whose infertility treatments had ultimately failed, burst into applause.

College-educated women now appear to have accepted as a virtual article of faith the idea that babies must take a back seat to graduate or professional school and to the establishment of a career. So the fact that several hundred well-heeled professional women with no particular political ax to grind would applaud the notion of earlier childbirth is surprising (especially since some, including Mitchell-Leer, had delayed childbearing themselves). But the session's participants, like thousands of other infertility specialists worldwide, have over the past ten or fifteen years met vast numbers of couples whose reproductive problems have stemmed at least in part from the age of the would-be mother. Many of these professionals, who have seen the costs of the trend toward delayed childbearing firsthand, now want women to be given a more realistic picture of their reproductive limits.

This concern has been voiced before, most notably in the early 1980s, in response to the publication of a French study revealing that success rates for artificial insemination markedly worsened with each upward tick in a woman's age. Alan DeCherney, then at the Yale University School of Medicine and now the chairman of obstetrics and gynecology at Tufts University Medical School and the president of the American Fertility Society (recently renamed the American Society for Reproductive Medicine), and the epidemiologist Gertrud Berkowitz, then also at Yale and now at Mount Sinai Medical School, were among those who recognized the implications of the report. In an editorial for the New England Journal of Medicine they declared, "If the decline in fecundity after 30 is as great as the French investigation indicates, new guidelines for counseling on reproduction may have to be formulated."

That no such public-health initiative was undertaken can be attributed mainly to social circumstances, which tended to militate against the very notion of such a program. The women's movement was still struggling with a radical bias against making babies (the "cruel institution of motherhood" is how the author Gena Corea once described the evolutionarily assigned role of the female in human reproduction). Furthermore, women of all stripes continued to fight for standing in the workplace. To announce during the Reagan years that the ideal time for a woman to have children was in her twenties was to align oneself, however unintentionally, with "pro-family" advocates who argued that a woman's proper place is in the home tending little ones.

Moreover, family-planning guidelines seemed mundane in the face of impressive developments in the field of reproductive medicine. During the 1970s gynecology had ceased to be a backwater and had begun attracting its share of medical schools' best and brightest. At the same time, researchers who had been experimenting for years with ways to manipulate animal eggs, sperm, and embryos had begun adapting their techniques to human beings. Armed with drugs to regulate hormonal cycles, new surgical instruments, and procedures for literally creating life in the lab, reproductive endocrinologists and gynecologists, along with their embryologist helpmates, assumed the status of latter-day fertility gods. Media reports conveyed the impression that the vagaries of reproduction had been brought under technological control.

In short, an array of social and scientific forces have encouraged collective wishful thinking about the functioning of the body, and increasing numbers of women have continued to put off childbearing without fully understanding the possible consequences of that choice. David Meldrum, a reproductive endocrinologist who has been at the forefront of reproductive technology since the 1970s, and who heads the Center for Advanced Reproductive Care, in Redondo Beach, California, says, "Women aren't told enough about the decline of fertility with age. Many don't realize that if they wait, motherhood may pass them by." A Canadian royal commission appointed in 1989 to examine advances in reproductive medicine and make policy recommendations asserted in its 1,200-page report to the government.

People who want to have children should be aware of the normal decline in fertility as they age and consider this in their decisions about when to have children. Such decisions have to take many factors into consideration, but a knowledge of the biological realities of postponing childbearing should be part of the information couples have available when making this choice.

John Collins, a professor in the department of obstetrics and gynecology at McMaster University, in Ontario, and one of hundreds of experts consulted by the royal commission, has put together a slide show that provides a persuasive visual summary of the "biological realities." Collins selected a dozen pertinent studies of female fertility, plotted data from each study on a standardized graph, and superimposed several curves on each slide. All the curves but one, which derives from a small and perhaps not broadly applicable study, proceed from the upper left to the lower right corner, from age twenty-six to beyond forty. A couple of curves are punctuated by a distinct steepening at around age thirty-one; several others take a bend at around age thirty-six. The remainder track steadily downward, supporting the argument that the ability to conceive erodes incrementally as women age.

Of course, everyone can think of exceptions to the younger-is-easier rule. "There are some women who—bingo!—go out and get pregnant at forty," says Jean Benward, a clinical social worker in San Ramon, California. But those who have waited to start a family only to find themselves locked out of childbearing can be emotionally devastated. Benward has counseled numerous women who, like her, came of age in the 1960s and never suspected that they would not be able to get pregnant whenever they chose. "Infertility is a shock at any age," she says, "but it has come as a particular shock to women of my generation."

For the American media, marketers, and politicians alike, the Baby Boom has served as a kind of background radiation—a demographic version of the vestigial heat from the Big Bang, 2.7 degrees Kelvin, which bathes the cosmos. But the trend toward delayed childbearing is more properly the background radiation, with the Baby Boom flaring against it as an anomalous supernova. In Western nations the tendency for couples to marry later and have fewer children, at an older age, has been at work almost since the beginning of the Industrial Revolution.

As is by now commonly known, patterns of childbearing in the United States have shifted over the past three decades or so as women have entered the work force en masse. According to tables compiled by the National Center for Health Statistics, 66.7 percent of women aged twenty to twenty-four were childless in 1992, as compared with 47.5 percent of that age group in 1960, near the end of the Baby Boom years. More tellingly, 43.8 percent of women twenty-five to twenty-nine and 26.1 percent of women thirty to thirty-four were childless in 1992; in both cases this is almost double the corresponding percentage of those who were childless in 1960. Today roughly a quarter of all first-time births are to women thirty to forty-four years old, and the phrase "elderly prima gravida," traditionally employed by physicians to refer to women entering motherhood over thirty-five, sounds absurd in a whole new way.

The subject of delayed childbearing has filled many column inches in newspapers since the late 1950s and has all but dominated discussions of pregnancy in women's magazines, which no doubt shape as well as reflect social attitudes, and are influential dispensers of health information in any case. "CAREER BABIES," read a March, 1958, Mademoiselle headline; "Over 30? Over 35? Over 40? How Late Can You Wait To Have a Baby?" was an article that ran in the January, 1976, Ms.—just two examples among dozens of pieces appearing in Vogue, Harper's Bazaar, Glamour, Cosmopolitan, Good Housekeeping, McCall's, Redbook, Essence, Ebony, and Ladies 'Home Journal which dealt explicitly or implicitly with the phenomenon.

Such articles generally extolled the virtues of older motherhood and promulgated the myth that women can easily conceive any time until their early forties—maybe, considering those flukish change-of-life pregnancies, even up to menopause. In the 1960s women's magazines devoted considerable space to the increases in the risk of genetic defects, particularly Down syndrome, that come with advancing maternal age. But the advent of sonography, amniocentesis, and chorionic-villus sampling to gauge the health of the fetus tended to assuage worries, and coverage became almost universally upbeat. The intent was clearly to support women who put off having children in favor of furthering their educations and establishing careers, and to reassure those whose life circumstances had thus far worked against their desire to have children—for example, women who had not yet found a mate and were unwilling to undertake single parenthood. The author of a 1989 New York magazine article on women in their mid-forties having children expressed a fairly typical view in declaring of her subjects,

They are part of the first wave of baby-boomers, and they are intent on pushing old age back as far as they can push it. They are a tough, feisty, indomitable group of women who are redefining what it means to age in the most profound way they can—by having babies who will enter kindergarten after their mothers have celebrated their fiftieth birthdays.

Leaving aside all questions about the merits of older parenthood, and also the question of whether this putative indomitability might not also constitute a profound form of denial, such stories may be said to create the impression that any pre-menopausal woman who wishes to have a child may do so at will. A necessary corrective comes when one delves into the demographic literature.

Ever since the invention of statistics, at the turn of the nineteenth century, heads of nations have paid particular attention to the procreational habits of their citizens. Censuses have been taken, and marriage and birth certificates filed, so that statisticians in their bureaucratic warrens, tallying and manipulating the data in dozens of arcane ways, can sketch profiles of given populations. Deceptively dry-looking on the page, these columns of numbers and percentages, of figures broken out by age or race or sex or educational attainment, have often prompted paroxysms of national concern and dismay—as, for example, in the 1860s, when a rising birth rate in Germany in conjunction with a stationary one in France led to nervousness among the French, who believed that population growth bore a strong relationship to military might.

In attempting for predictive purposes to comprehend both the patterns underlying population fluctuations and the ways in which biological and societal forces interact to yield booms and busts, researchers began to distinguish between fertility, or the actual bearing of children, which is usually stated as a total number or rate per thousand women, and fecundity, or the capacity of a woman to conceive. (Medical scientists also speak of "infertilityz by which they may mean either the condition of childlessness or a difficulty in conceiving; in referring to the latter state, statisticians often prefer the term "impaired fecundity.")

Demographers have struggled to explain why younger women invariably register higher fertility than older ones. The obvious answer is that the female reproductive organs become less efficient with age, but establishing the truth of this is not as easy as one might think. To prove that the decline in fertility results from a deterioration of physiological function, one must separate out the effects of behavior from those of biology. The ideal for theoretical purposes would be a robust population in which breeding occurs without impediment over the entire reproductive lifetime of the female. Scientists have easily constructed such experiments with animals, and all the animal data support the hypothesis of an age-linked decline in fecundity. The situation is more complex with human beings, however. Modern populations do not in general approximate the required conditions, because surgical sterilization and contraceptive use are widespread. So demographers have turned instead to the study of small interbreeding groups that have not practiced contraception.

Perhaps the classic paper in this genre, by Joseph Eaton and Albert Mayer, sociologists from Wayne University, was published in a 1953 issue of Human Biology. Eaton and Mayer realized that records kept from 1880 to 1950 by the Hutterites, an Anabaptist sect living in scattered settlements in the Dakotas, Montana, and Canada, provided a means of carrying out "an ex post facto experiment in human biology." Close-knit, and meticulous about keeping their vital statistics, the Hutterites also observed a religious proscription against birth control. Eaton and Mayer saw that the Hutterites might help to answer the question "How many children can a group of human beings have if they reproduce up to the limit of their biological capacity and live through their entire period of potential fertility?"

The Hutterites proved to be extraordinarily fertile, registering a higher birth rate than any group previously examined. But more intriguing for demographers was a curve demonstrating that a Hutterite woman's chance of a live birth at a given age—her reproductive batting average, as it were—fell from just over .500 at age eighteen to .000 shortly after age forty-eight, with the curve taking a sharp bend southward at around age thirty-five. The Hutterite study became a standard reference, and its findings were bolstered in 1961 by a comparative survey of ten similar populations from around the world. But critics found possible reasons other than underlying biology for fertility drops: for example, sexual ennui—or, as they more technically put it, a diminution in coital frequency over the course of a marriage. The age of the male partner could also play a role, in part because the volume, vigor, and viability of sperm seem to begin to diminish around forty.

Demographers continue to debate interpretations of fertility figures and to question one another's methodologies and theoretical assumptions regarding the measurement of age-specific declines in fecundity. Yet although no consensus has emerged, statisticians such as William Mosher, who heads the Family Growth Survey Branch of the National Center for Health Statistics, and his colleague Anjani Chandra, who has written extensively on the demography of infertility, straightforwardly assert that "in women, fecundity decreases with age, particularly after the age of 30 or 35 years." Chandra says that one "could rage on forever about the actual critical age" at which fecundity sinks most sharply, but she thinks that virtually everyone agrees that the decline exists. "The truth of the matter," says James Trussell, an economist at Princeton University who is affiliated with the Office of Population Research there, "is that evolutionarily, women are designed to have children early. Of course, socially, things aren't designed that way."

Physicians, and gynecologists in particular, soon became aware of demographers' Sputnik-era discussions about fecundity, although the subject commanded only passing interest, because in those days infertility could not be overcome medically. Nonetheless, in the 1970s French medical researchers saw that they, like Eaton and Mayer, had been presented with a form of human biology experiment, an opportunity to arrive at a baseline reading of female fecundity.

Early on, French sperm banks and infertility centers had banded together under a single organizational umbrella. The Centres d'Etude et de Conservation du Sperme Humain, known by the acronym CECOS, had adopted standardized approaches to freezing and handling sperm and to treating patients. Around 1973 several CECOS researchers realized that by performing artificial insemination with donated sperm on a group of reproductively healthy but childless women of mixed ages who had come to the centers because their husbands were sterile, they could arrive at an approximation of "natural" fecundity. Artificial insemination under controlled conditions would eliminate confounding factors such as variations in coital frequency or in sperm quality.

By the time the CECOS clinicians wrote up their results, they had followed 2,193 women over the course of seven years, 1973 to 1980, and had observed a "slight but significant" decrease in the ability to conceive after age thirty and a "marked" decrease after age thirty-five. Whereas women under thirty-one had about a 74 percent chance of being impregnated within a year's time, the figure fell to 61 percent for those aged thirty-one to thirty-five, and to 54 percent for those over thirty-five. These were the numbers that prompted DeCherney and Berkowitz's New England Journal of Medicine editorial on the need to rethink delayed childbearing.

The French researchers drew fire from a few demographers who, though confirming the trend, dismissed their numbers as too high. Meanwhile, infertility specialists hit upon a new angle from which to examine fecundity. As growing numbers of women underwent treatment with fertility drugs and attempted to conceive through in vitro fertilization, researchers tallied successes and failures according to age group. Almost invariably, older women had a poorer prognosis than younger ones. The test-tube-baby pioneers Patrick Steptoe and Robert Edwards observed this disparity among their patients in a 1983 progress report in The Lancet, and it was seen again and again in programs around the world, with the worst outcome being among women over forty, whose chances of conceiving turned out to be quite slim even if the fertility problem apparently lay with their partners.

Some researchers, puzzling over what could account for the ill fortune of older women, zeroed in on poor egg quality as a possible cause. This "bad eggs" explanation has gained widespread acceptance since the introduction, in 1983, of egg donation, a procedure in which a physician inserts a needle into the ovaries of one woman, sucks mature eggs from her follicles, combines the eggs with sperm, and then transfers the resulting embryos to a second woman, who hopes to carry one or more of them to term. In the bulk of cases, infertility specialists have found, older women who fail to become pregnant using embryos made with their own eggs succeed when the eggs come from a younger donor.

The work of the reproductive endocrinologists Mark Sauer and Richard Paulson and their associates at the University of Southern California School of Medicine has demonstrated in dramatic fashion the difference that young eggs make. From their clinic in downtown Los Angeles, Sauer and Paulson have inadvertently made a name for themselves in the tabloids by helping women old enough to be grandmothers get pregnant. Last year Sauer and Paulson reviewed the results of 300 egg donations carried out at their clinic, 198 of them in women aged forty to fifty-nine, and concluded that the natural aging of eggs accounts for the decline in female fecundity. Sauer and Paulson feel certain of this because even postmenopausal women who received donated eggs were able to undergo successful pregnancies, as long as they were given hormones to plump up the uterine lining.

Embryos from older eggs show no external signs of being flawed. Magnified and floating in culture medium, an eight-cell human embryo produced from a forty-year-old woman's egg cannot be differentiated from that of a teenager. But the eye is no gauge of embryonic fitness. Recently a team of scientists at Cornell University Medical Center, in New York City, provided compelling evidence that abnormalities deep within developing embryos account for failures of in vitro fertilization, and that these abnormalities occur with greater frequency among older women.

We have known since the 1930s that as women age, they are far more likely to produce fetuses and babies with Down syndrome and other "trisomic" anomalies. Embryos that are trisomic contain, instead of matched pairs of chromosomes, one too many of a given chromosome, most commonly chromosome 13, 18, 21 (which is responsible for Down syndrome), X, or Y. Trisomies are the result of a glitch known as nondisjunction, which occurs principally during the creation of egg cells (although sperm cells may also exhibit such errors). Immature human eggs, or oocytes, sit in suspended animation in the ovaries from the time they are formed in the female fetus, and complete the process of meiosis to form mature egg cells only just prior to ovulation. When nondisjunction occurs, the resulting eggs may carry too few or too many chromosomes, a state called aneuploidy.

In a 1983 letter to the journal Nature, British in vitro fertilization researchers conjectured that embryos formed from such botched eggs would be less viable than those with a normal genetic endowment, and either would not implant in the uterine wall or would spontaneously abort shortly after implantation. This, they said, could account for the generally high rate of in vitro failures then being seen—about 80 percent. The further implication, arising out of the well-known correlation between maternal age and chromosomal disorders, was that the longer oocytes sit around in the ovaries, the more likely they are to rub the series of steps vital to dividing up the chromosomes.

This notion has been borne out by the Cornell team, which made its case in one of the main papers presented at last fall's American Fertility Society meeting. Jamie Grifo, a reproductive endocrinologist who also holds a doctorate in biochemistry and is an assistant professor of obstetrics and gynecology at Cornell, read the paper, which had taken top honors from the Society for Assisted Reproductive Technology. Grifo and his colleagues have been fine-tuning an experimental method for diagnosing chromosomal abnormalities in embryos before they are transferred to women undergoing in vitro fertilization (the aim being to help couples at high risk of passing on genetic diseases). The test involves removing one cell, or blastomere, from an eight-cell embryo and exposing the cell to flagged fragments of single-stranded DNA, which bind to the chromosomes and can be viewed, glowing, under a special microscope. If the blastomere is aneuploid, this molecular tool, called "fluorescence in situ hybridization," or FISH, will unmask it. Grifo announced at the meeting that in screening normal-looking pre-implantation embryos from two groups of women, twenty-five to thirty-nine years old, and over thirty-nine, they had found significantly higher proportions of aneuploidy in the second group than in the first—42 percent as against nine percent.

The team has further illuminated the extent to which eggs go bad with age in an unpublished paper written by the geneticist Santiago Munne. Munne reports that FISH screening of 3,594 blastomeres from 514 pre-implantation embryos pinpointed far more aneuploidies among women over forty than should have been expected, given the rates of aneuploidy tallied from amniocentesis tests of fetuses carried by older women and from live births. In other words, more aneuploid embryos are formed than ever show up as pregnancies, and more pregnancies with aneuploid embryos spontaneously terminate at some early stage than ever continue to term. Nature, it appears, has a mechanism for weeding out embryos of inferior quality, whether they're made in a petri dish or in the body.

Grifo and the Cornell team contend that genetically faulty embryos are the main cause of the high failure rate of in vitro fertilization among older women, but other fertility specialists have reservations. Richard Paulson, who was a physics major as an undergraduate, professes to being something of a stickler when it comes to data; he is not entirely persuaded by the Cornell numbers and suggests that flaws in aging eggs other than chromosomal ones might bar their implantation and development. David Meldrum, of the Center for Advanced Reproductive Care, who has made a review of the literature on female reproductive aging, contends that both egg quality and uterine receptivity play a role in the decline of fecundity with age. But whatever the locus of the problem, pregnancies prove harder to establish and maintain in older women—whether in the infertility clinic or in the world at large. Women in their forties are known to have a rate of spontaneous abortion half again as high as those in their twenties. And the older a woman gets, the greater her prospects of bearing a premature or low-birth-weight infant, or of having a stillbirth—and thus the greater her possibilities for heartache.

The natural reduction in reproductive capacity can be considered an unavoidable part of being human. But in weighing the potential liabilities of delayed childbearing, the slings and arrows of personal fortune must also be considered. Every woman is an individual, and as all college students learn, statistics apply to populations, not people. Whether any particular woman will have difficulty conceiving if she delays childbearing depends in part upon her history and family heritage. For example, the more sexual partners a woman has had, the greater her risk of having been exposed to a disease like chlamydia, which can spread into the pelvic region and cause inflammation and scarring, rendering the passage of ovulated eggs down the fallopian tubes difficult or impossible. Pelvic inflammatory disease, which is often asymptomatic, has been on the rise since the 1970s, and is thought to have affected some 11 percent of women in the United States. Smoking, exposure to chemicals in the workplace and home, and the use of alcohol and other drugs have also been shown to undermine fertility. Women in their forties have higher incidences of cervical, uterine, and ovarian cancer, the ravages of which may leave them incapable of bearing children.

Dorothy Mitchell-Leef and other infertility specialists have expressed concern as well about the number of women they are seeing with premature ovarian failure, or early menopause. Normally, women in the industrialized world go through menopause between the ages of forty-nine and fifty-one. Outwardly marked by a cessation of menstruation, menopause is caused by the depletion of eggs in the ovaries. The store of eggs—some 6 to 8 million in female fetuses—begins to dwindle even during gestation, and eggs continue to be lost throughout girlhood and adulthood by attrition and with each menstrual cycle, until, finally, too few eggs remain to maintain the monthly reproductive cycle. In the past year or so Mitchell-Leef has seen what she considers an unusually large number of women in their mid-thirties to early forties whose hormone levels indicate that they are entering menopause. Last fall she saw ten such patients in two weeks alone.

Because no population-based studies of premature ovarian failure have been performed, and even the anecdotal evidence is not being widely reported, probably the best interpretation for the time being (from a scientific, not a humane, point of view) is that the patients walking into Mitchell-Leef's clinic represent a statistical blip rather than an early warning signal of a major public-health problem. But even without an epidemic of premature ovarian failure, the overall reproductive health of American women is a matter of some concern.

In 1990 William Mosher and William Pratt, at the National Center for Health Statistics, performed an analysis of information gathered in the 1988 National Survey of Family Growth, in which 8,450 women, selected as representative of the population at large, were asked about their reproductive histories and health. Extrapolating from their answers, Mosher and Pratt projected that 8.4 percent of women in the United States, or about 4.9 million of the 57.9 million women aged fifteen to forty-four, could be categorized as having impaired fecundity. When Mosher and Pratt broke out the figures by age, the percentage of those expected to suffer from impaired fecundity increased in stepwise fashion. Falling into that category were 4.1 percent of all American women aged fifteen to twenty-four (some 614,000 women), 13.4 percent of those aged twenty-five to thirty-four (972,000 women), and 21.4 percent of those aged thirty-five to forty-four (620,000).

In part because the survey relied on women's own awareness of their reproductive health, which could be incomplete, the incidence of impaired fecundity appeared greater among married than among unmarried women. The phenomenon was particularly pronounced among childless married women. The survey suggested that approximately 1,037,000 of these women aged twenty-five to forty-four had tried to get pregnant and couldn't, or had had intercourse with a spouse for three years without using contraceptives and had failed during that time to become pregnant, or had been told by a physician not to become pregnant because it might endanger their health, or knew that they could not become pregnant, owing to a previous accident, an illness, or an "unexplained inability to conceive," a condition referred to in medical jargon as idiopathic infertility.

Statisticians have no idea how many women who want children reach the end of their childbearing years without fulfilling that desire, or how many would have liked to have more children than they had but were unable to because of impaired fecundity. The 1992 Current Population Survey, carried out by the Bureau of the Census, estimated that of the 44 million childless U.S. women aged eighteen to thirty-nine, some 15 million expected to have one child or more during her lifetime. About a third of these women were aged thirty to thirty-nine. Even the most conservative National Center for Health Statistics estimate—that one in twelve women suffers from impaired fecundity—suggests that some 350,000 to 700,000 women could encounter impediments to their plans.

Gynecologists and obstetricians argue that the majority of women who want to have children will conceive, and indeed this is true. But as David Meldrum says, "The cup they are looking at is half full, and the one we're looking at is half empty." The one-in-five rate of impaired fecundity among all childless women aged thirty-five to forty-four, and the one-in-eight rate for those aged twenty-five to thirty-four, don't strike this observer as amounting to terribly good odds. They're not cause for panic, but they are worth mulling over. John Collins, of McMaster University, says, "Clinicians should tell women, 'These are the facts, and you see how that fits in with the remainder of your life.'" He believes that his approach—to empower women with information rather than advise them to get pregnant at a certain age—comports with that of the majority of his colleagues. Jean Benward, the California social worker, says, "People's life trajectories are very complicated, and circumstances are not always within our control. Knowing the facts may not have an impact on a woman's behavior, but I think it's valuable for women to have the information so that they can make informed choices."

Of course, those who, having delayed parenthood, find themselves unable to conceive naturally can choose to enter the high-tech world of assisted reproduction. But this path is generally costly (patients must pay tens of thousands of dollars out of their own pockets, because only a few states mandate insurance coverage for infertility treatments), as well as unpleasant (women undergo painful daily injections of fertility drugs, frequent blood tests, general anesthesia, and invasive surgery). Medically mediated conception is also time-consuming and encourages a kind of obsessiveness. Some women, among them the journalist Anne Taylor Fleming, who has written a disquieting account of her own unsuccessful attempts to have a child in Motherhood Deferred, spend the better part of ten years in and out of infertility clinics. If artificial insemination and the various in vitro fertilization options fail, women who want children but don't want to adopt now face the ethical and other quandaries built into two exotic new alternatives: trying to become pregnant using another woman's egg, and enlisting a surrogate mother.

The unfortunate bottom line is that infertility specialists cannot help all couples who seek their services. Even leading clinics using the latest procedures offer no guarantees. True, a certain number of couples who don't succeed by high-tech means go on to achieve pregnancies by the old-fashioned method. But many others are left childless, in debt, and anguished over their failed dreams.

Some reproductive endocrinologists point out that when researchers learn how to freeze eggs (so far, sperm can safely be frozen and thawed, as can embryos, but eggs have proved refractory), women will be able to consign a clutch of young eggs to the cryopreservation tanks when they are twenty and reclaim them at a later date. Clever as that sounds, it seems a highly impractical solution to the problem. As already noted, egg retrieval is expensive and invasive. Without a radical restructuring of health care, few women would be able to take advantage of an option like egg cryopreservation.

Perhaps there's another way. Suppose America put its money where its mouth is on family values. Politicians endlessly invoke that shibboleth, yet the United States—notwithstanding the Family and Medical Leave Act signed with much fanfare by President Clinton in February of 1993—still offers far less social support for childbearing than do most other industrialized countries. Luxembourg, whose state-mandated maternity and parental leaves are among the least generous in the European Union, provides women with up to ten weeks of paid maternity leave and gives parents the option of unpaid absences for certain periods until their children are fifteen years old, with the guarantee of a job upon their return. Italy, whose policies are among the most generous in this regard, gives women up to five months' fully paid maternity leave, and has a proviso allowing either parent to take two or three days at a time off to care for a sick child under three years old. Paid maternity and parental leaves and safe, affordable day care, which are taken for granted by citizens of other nations, remain out of reach in the richest economy in the world.

Women's-rights advocates have been fighting for a century for equity in the American workplace, and still have to deal with corporate bias. Sixty years ago few companies thought twice about firing a female employee who became pregnant; now the discrimination against women who have children is more subtle but nevertheless tangible, as they are shunted off into corporate backwaters or kept out of consideration for partnerships or passed over for pay raises. Women delay childbearing for a variety of reasons, but surely important among these is the need to establish themselves professionally, and the awareness that opportunity and credibility are elusive, particularly if they become mothers.

Felice Schwartz, in her incendiary 1989 Harvard Business Review article "Management Women and the New Facts of Life," which caused the "mommy track" brouhaha, contended that women are more prone to "career interruptions, plateauing, and turnover" than men, and that these all cost companies money, in lost training dollars and in lost expertise, when middle- and upper-level women retire to the nursery. Aside from the fact that "career interruptions, plateauing, and turnover" reads like the resumes of a substantial number of middle-management Baby Boomers in this age of downsizing and globally free-floating corporate dollars, one must seriously question, as Schwartz herself did, whether these are the inevitable consequences of motherhood or an artifact of national social policies.

Notwithstanding subsequent misinterpretations and misuses of her thesis by corporations and feminists alike, Schwartz concluded that the majority of women "want to pursue serious careers while participating actively in the rearing of children," and suggested that employers should help women to "plan for and manage maternity" and should act to "make family supports and high-quality, affordable child care available to all women." That such an approach can yield good results can be seen in Sweden, where government and corporations have made a concerted effort since the 1970s to encourage women to enter the workplace. There, generous parental leave, excellent public day care, and job flexibility have allowed women to balance work and motherhood with aplomb.

Women today make up almost half of the work force in the United States, and the proportion continues to rise. Two thirds of women with children are employed. In light of the biological realities they face, women would do well to continue to press for a reconfiguration of society, so that they might, if they chose to, have babies in their twenties and develop their careers in their thirties—as suggested by Alan DeCherney and Gertrud Berkowitz in the wake of the CECOS study. In order for that to be possible, society will need to amend itself in ways that are likely to redound to the benefit of not just women but everyone.