Woman

by Natalie Angier

  Women who like the effects of estrogen therapy, who feel smarter and more energetic with it than without, need no persuasion. They will be proactive patients, and many will be prosely-tizers too, telling their friends at the menopause Maginot, Try it, you won't be sorry. But the women who are noncompliers—what of them? Are they necessarily ill-informed or misguided? Some may resist taking hormone therapy because they're afraid of breast cancer. Or they may try it but dislike the side effects, the breakthrough bleeding, the tender breasts, the moodiness, aque-ousness, nausea, the pimples—symptoms so reminiscent of the premenstruum. Many women simply resent the implication that menopause is a disease, and they express their resistance by tossing their pills in a drawer and forgetting the whole business. Women in their fifties often feel quite fit. They remember when women were considered unsuitable for higher office because of their fluctuating hormones, and when women had to quit a job the moment they became pregnant. Enough is enough; enough queasiness over the female body. Must a woman go to her grave with a speculum chained to her thigh? Menopause is an event, just as menarche was, a female rite. Their mothers and grandmothers went through menopause, their friends go through menopause. It happens to everyone. Women can't help but feel that menopause is natural. They say as much to their doctors—menopause is natural. It's meant to be, it's what the body does, and why shouldn't I be pleased with, or at least tolerant of, what my body brings me?

  Doctors have responded badly to this interpretation of menopause, this self-satisfied talk. They're faced with a challenge. If they're going to persuade large numbers of healthy women to take hormone replacement, they must dispel the notion of the good and natural menopause. They must raise the specter of infirmity, a weakening heart, a crumbling frame, an enfeebled mind. They contrast a woman's spectacular loss of ovarian estrogen with a man's far more gradual tapering of testosterone levels: he ages gracefully, you age overnight. They describe menopause as a state of "estrogen deficiency," comparing it to endocrine disorders such as hypothyroidism and diabetes. Just as a diabetic should be treated with insulin, so an estrogen-deficient woman should be treated with HRT, and any woman past fifty is almost by definition estrogen-deficient. Even women who are still menstruating may be estrogen-deficient, may be "perimenopau-sal," as the melodious little phrase has it, and candidates for hormone therapy. If a woman asks why it might be that all women lapse into this precarious state of hormone deficit in midlife and why nature has not better equipped them for their sovereign years, a doctor will reply, If it were up to nature, we wouldn't be having this conversation and I wouldn't be writing this prescription. A long life is good, it is desirable, it is a tribute to human ingenuity and modern medicine, but one thing it decidedly is not is natural. If it were up to nature, you, my post-reproductive doyenne, would already be dead.

  Or would you? Let's ask that old woman out there in the field, the one with the shovel in her hands. She's digging up something, and it sure doesn't look like her grave.

  13. THERE'S NO PLACE LIKE NOTORIETY

  MOTHERS, GRANDMOTHERS, AND OTHER GREAT DAMES

  THE HADZA PEOPLE are a small group of hunter-gatherers who live in the dry and rugged hill country of the Eastern Rift Valley, in northern Tanzania. There are only about 750 of them, but they're not going anywhere. They speak a distinct language, Hadza, a percussive tongue of clicks and hisses reminiscent of but unrelated to the language of the !Kung. And the Hadza refuse to be domesticated. Time and again over the past sixty years, church and government agencies have tried to transmute them into farmers, but the efforts always fail and the Hadza return to the bush. They hate gardening! They hate milking cows! Instead, the Hadza subsist almost entirely on wild pickings—game, berries, honey, tubers. They're opportunists: see an impala, kill an impala. If the berries are ripening three miles away, they move three miles away. When the local bees slacken their honey production, the Hadza break camp to find busier ones. On occasion they'll steal a sheep from a neighboring herder, but usually they prefer barter, giraffe jerky for maize or tobacco.

  The Hadza live a no-frills existence that supposedly retains some features of the Pliocene and Pleistocene conditions under which Homo sapiens evolved. They're Stone Age relics, more or less, which is why they attract the attention of Western anthropologists. What can they tell us about the essential us? For one thing, forget Hobbes. The Hadza's lives are not nasty or brutish, nor are they particularly short. As Kristen Hawkes, of the University of Utah, discovered when she and her colleagues descended on the Hadza and tracked their life histories, the women refuse to do what our forebears are said to have done routinely—die by the time their eggs have run out. No, many Hadza women keep on going well past menopause, into their sixties, their seventies, sometimes their eighties, all without the purported life-extending benefits of the postindustrial age or even of the agricultural revolution. In the United States, demographers worry about the aging of the population and the potential drain of the elderly on the wealth and patience of the rest of us. The Hadza might worry about the opposite, what would happen if they didn't have their corps of old ladies. As the data from Hawkes and her colleagues reveal, postmenopausal Hadza women are the hardest-working members of the tribe. Every day they're out in the bush, digging, poking, reaching, clambering. They gather more food than any of their comrades. They share their food with young relatives who can't fend for themselves: grandchildren, great-grandchildren, great-nieces and -nephews, second cousins twice removed. When a young woman is breastfeeding a newborn and can't forage as effectively as usual for her older children, she turns for assistance not to her mate (where has that man got to now?) but to a senior female relative. Grandma, or her proxy, takes up the slack and keeps the kids in baobab and tubers. Hadza children are always thin, but without an elder's efforts they would become too thin, Karen Carpenter thin, whenever a new sibling arrives, and they might very well die early as a result. Hadza elders are truly great grandmas. They are not an option. They are not a Hallmark sentiment. In Hawkes's study, no nursing mother lacked a postmenopausal helper.

  The Hadza are a small group. They have had extensive contact with bureaucrats, academics, cultural carpetbaggers, and exhorta-tionists of all stripes, including some of their own members who received a Western-style education and came back preaching the gospel of agraria. The Hadza are not "pristine," and it's risky to draw too many conclusions about prelapsarian humans from them or any of the other hunter-gatherers remaining in the world. Nevertheless, if we're going to talk about the evolution of human menopause and squabble over whether it's natural or unnatural, meant to be or an unfortunate tag-along of our newfound longevity, we can't ignore all those Hadza matriarchs rooting around in the woods for the fruits of the future. To Grandmother's house we go.

  The "grandmother hypothesis" of the origins of human menopause got its start in a paper that is nearly old enough to be a grandmother itself. In a classic 1957 essay about the charming inevitability of aging, the renowned evolutionary biologist George C. Williams addressed the strange case of the climacteric. He pointed out that most depredations of age, such as failing eyesight, arthritis, wrinkling, and the imperialism of flab, occur at varying rates and to varying degrees among individuals. Some aspects of aging can be forestalled for decades, through exercise or by wearing a hat in the sun. Not so menopause. Whatever a woman does, however rigorously she attends to her health, at the half-century mark, give or take a few years, she will go into what Williams called "premature reproductive senescence." Not every person ends up needing reading glasses, but all women who reach the age of menopause stop ovulating. By contrast, other female mammals, including our close relatives the apes, continue bearing young practically to the grave. Orangutans do not go into menopause. Chimpanzees do not need extract of mare pee. Men too can father children they may be too arthritic or cataracted to hold or behold. Only in human females, Williams said, does the fertility program shut down years before death. How unlike nature, in designing women, to forget her
beloved multiplication tables.

  For the apparent conundrum Williams proposed a brilliant solution: blame it on the kids. Human children are so damned expensive. Each one requires years and years to rear to independence—thirteen or fourteen years at a minimum. They need to be fed, clothed, housed, schooled in whatever skills their environs require, protected from the wrath of the bored and the bullying. Assuming that mothers have always been the primary caretakers of their children and that in the past a child without a mother was a child without a prayer, Williams suggested that it behooved a woman to persist long enough to usher her children to puberty and autonomy. If a woman remained fecund to the bitter end, becoming pregnant even as her body was faltering, she risked dying in childbirth or its draining aftermath when she still had several dependent young. And all those kids could very well die in her wake, or at least fail to reach their potential. Better the woman should forgo the hazards of late-stage maternity and devote herself to mothering the children she already had. Better her ovaries should be programmed to senesce in advance of the rest of her. Better she should live to be a grandmother.

  The Williams hypothesis was an instant success. Everybody loved it, especially women over fifty. It had the same clever, simplified appeal as Desmond Morris's proposal that a woman's breasts are bowsprit buttocks. Menopause is natural. It's built into the system, a registered trademark of humanity. We're smart, our kids are smart, and our ovaries show it: they cease production just in time to give us a fighting chance to see our last child out the door. Menopause is good, and it can feel good; Margaret Mead famously talked in the 1960s of the "zest" of the postmenopausal woman.

  Others seized and expanded on the hypothesis. Jared Diamond, of the University of California at Los Angeles, has argued that older women have been crucial in human history not only for their mothering skills but as repositories of information, Alexandrian libraries for preliterate tribes. Elders keep track of where the edible plants are, and they can recall natural disasters of long ago that may have affected the distribution and safety of local resources. Writing of his experiences in New Guinea and the Pacific islands, Diamond has described how, whenever he would ask questions about the island's flora and fauna that stumped the young or middle-aged natives, he invariably would be led into a dark hut, where he would meet the Oldest Living Member of the Tribe—sometimes a man, but usually a woman—who knew the answer to his interrogations. It sounds like a trope of Rousseau's, or Hollywood's, but the wise elder had her synapses and priorities straight. Eat that plant, sir, and your body will shake and your eyes will bulge from their sockets and you will be dead by sunrise. Anything else I can help you with today? As Diamond sees it, young relatives profited from the memories and advice of old relatives, and so selection extended human longevity. Men can live for decades with spermatogenesis proceeding apace, but childbearing gets riskier over time. If women were to survive to the encyclopedia years, the mechanism of menopause had to be born.

  Jocelyn Peccei, who decided to go back to graduate school at UCLA when she was close to menopause and then chose to study—why not?—the evolution of menopause, has calculated that menopause might have arisen quite early in the hominid lineage, perhaps 1.5 million years ago, when we were as yet Homo erectus. But evidence to prove her proposition is hard to come by. Soft tissues such as ovaries do not leave fossils behind.

  The backlash against the organic grandmother began in the 1970s, coincident with attempts by the medical community to promote estrogen replacement therapy for middle-aged women. As doctors became convinced that estrogen is the primary reason that women don't usually have heart attacks until after menopause, they began to question the desirability and "naturalness" of programmed ovarian senility. The grandmother hypothesis posits that women stop ovulating so that they can live longer and tend to their existing young; why, then, would the cessation cut off the primary source of a wondrous hormone that can keep women alive? How silly and self-defeating. Surely the adaptationists must be wrong. Surely menopause was not selected by evolution but is, like gray hair, merely another sign of our decay. And just as gray hair can be dyed or highlighted into the verisimilitude of youth, so the worst side effects of menopause can, and should, be ameliorated with estrogen replacement therapy.

  The backlashers brought out the scorpion whips and cat-o'- nine-tails. Paleontologists argued that middle age and old age are themselves quite new. Until a few thousand years ago, they said, almost nobody lived past their early forties. The bones that have been found of early hominids are overwhelmingly the bones of young people. There are few if any postmenopausal women, no merry crones, in the fossil record. It's ridiculous to argue that natural selection has favored the onset of menopause in humans when early humans rarely lived long enough to enjoy hot flashes or Meadian zest. Women, and men, died by the age of forty-five. A woman's eggs will last her until about forty-five. As paleodemographers see it, the fit is pretty snug: a woman has all the eggs she needs to live the life she did when selective forces carved out the rudiments of our fate tens of thousands of years ago. If women today breezily outlast their egg supply and write best-selling books about the experience, fine, bully for them, but we're all artifacts of fortified food, purified water, and Jonas Salk, and evolution has nothing to say about us or our geriatric athleticism.

  Nor could anthropologists find support for the adaptive value of menopause among contemporary "primitives." In the 1980s, Kim Hill and Magdalena Hurtado, of the University of New Mexico, studied the Ache of the eastern Paraguayan forest, another group of hunter-gatherers who must shoulder the burden of prehistory's silence. The anthropologists amassed a large and exacting data set. They observed the help and succor that older Ache women gave to their children and grandchildren. They devised theoretical models comparing the indirect genetic benefits that the grandmothers reaped by devoting themselves to their existing children and grandchildren with the direct genetic benefits that the women would have accrued if they had been able to continue bearing babies past menopause. An adaptation supposedly enhances your reproductive fitness, the ability to throw your lovely and singular genetic garland into tomorrow. If the grandmother hypothesis were valid, then presumably the contributions that the elder Ache women made to the health and survival of their children's children should outweigh the genetic gains of having two or three more children of their own. Alas, the bonus babies won: the anthropologists concluded that the Ache grannies were making surprisingly little difference to the prospects of their grandchildren and that the seniors would be better off—from a strictly Darwinian standpoint—if they could be mothers past menopause.

  Through mathematical simulations, Alan Rogers, of the University of Utah, reached a similar conclusion. In a 1991 paper, he estimated that a woman would have to be a comic-book heroine, Neutron Nana, to make menopause look like an adaptation. Her ministrations to her family would have to double the number of children that all her children bore and help keep all her grandchildren alive to give premature reproductive senescence an edge over maternity in haghood. Even Demeter, the great goddess of the harvest, couldn't prevent her daughter, Persephone, from going to hell for six months of the year.

  I was reared at the knee of the grandmother hypothesis. Even as a girl whose menopause was decades away, I found comfort in the idea that when it happened, it was all part of an optimal design. The thought of it linked me to my mythical ancestors, those dusty, lanky, demimonde women striding across the veldt, their brains expanding with every step. Hence I despaired when, in the 1990s, the facts seemed stacked against it. Many of the scientists I talked to thought it was a charming notion, but probably wrong. "Adaptive menopause is an interesting idea, and I wish I could believe in it," Steven Austad, a zoologist at the University of Idaho, said to me in mid-1997. "But I just don't see the evidence to support it." And from Alison Galloway, an anthropologist at the University of California in Santa Cruz: "I don't buy the Grandmother Hypothesis. I don't think there's anything beneficial about menop
ause. I don't think it's been selected for. It's the result of recent expansions in our lifespan. We outlive our follicles." Margie Profet, architect of the menstruation-as-defense theory, told me that it didn't matter, in an evolutionary sense, if postmenopausal women lacked the protection menstruation afforded: women weren't supposed to live past fifty. Jane Brody, my colleague at the New York Times and a proponent of hormone replacement therapy, has written that women shouldn't worry about hormone therapy's being unnatural, because a "woman's current life expectancy, on average, of seventy-seven years is not natural either."