Mother and child disunion: don't take a mother's love for granted.

Shortly after arriving in Taiwan in 1957, Stanford University anthropologist Arthur Wolf reached the rural village of Hsia-ch'i-chou. There, he met a weathered-looking woman who told an incredible story. Several decades previously, she had given away her five infant daughters and had replaced them with five girls adopted from other families and fated to become wives to her five sons. The friendly, outgoing woman seemed proud of what she'd done, Wolf recalls, adding that she described the dispatching of her babies to new homes as smart household management.

"I gave away all five girls and raised instead wives for my five sons," Wolf remembers her saying. "This saved me [money and ultimately the need to pay dowries] as well as the trouble of arranging 10 marriages." For each marriage of an adult son, for example, she would have had to throw large and expensive feasts, as well as pay a fee to the bride's family.

The same pragmatic outlook characterized many other women whom Wolf encountered in his fieldwork in 11 villages and two small towns in northern Taiwan. To these women, Wolf reports, shipping out their daughters--sometimes to families living just down the road--and adopting future daughters-in-law were the right things to do.

Wolf refers to the outcome of this early childhood matchmaking as minor marriages. The bride in a minor marriage was considered to be a daughter-in-law as soon as she reached her new family, even if she was only a month or two old. An official marriage ceremony occurred shortly after both members of the couple reached puberty.

For several decades, Wolf studied such marriages to test a theory about incest taboos. However, a few years ago, Wolf decided to consider minor marriages from a broader perspective. He sifted through adoption data from 1905 to 1945 for the 13 communities that he had visited, and, with several colleagues, he obtained comparable records for parts of central and southern Taiwan, as well as for the nearby Pescadores Islands.

Many social scientists and biologists, including Wolf, had assumed that natural selection yields women who are disposed to feel a deep attachment to their helpless offspring. After all, babies seem to elicit more love from their mothers with every coo and suckle. And mothers often report intense emotional pain when separated from their babies.

The Taiwanese data threw a monkey wrench into those deeply held assumptions. In northern Taiwan, 3,046 women had given up a majority of their 6,201 daughters for adoption by age 1 and as many as 80 to 90 percent by age 15. A comparable wave of daughter giveaways had occurred in the Pescadores. Given a convenient alternative to raising daughters whom most adults in these locations refer to as "useless things," Wolf says, women willingly relinquish the girls as child brides.

For reasons that remain unclear, minor marriages became popular only in northern Taiwan and the Pescadores. In central and southern Taiwan, most mothers had raised their own daughters. In yet other cultures, mothers might resort to a more extreme measure, such as infanticide, to deal with unwanted children.

In the northern Taiwanese society, the husband controlled family resources and his parents shared the house. Therefore, the raising of daughters-in-law may have provided the mothers with much-needed allies. This practice also helped these mothers preserve their sons' loyalty. Otherwise, a grown son might marry a woman who would convince him to promote her ideas on how to run the household, leaving his parents at her mercy.

The unusual practice of minor marriage, chronicled in the Dec. 2003 Current Anthropology, highlights what Wolf calls a stimulating contradiction: Although intense maternal sentiments typically weld mothers to their offspring, when socially acceptable alternatives are available, women often give away children they don't need.

It seems that bearing and caring for a child aren't sufficient to arouse a mother's love, Wolf concludes. Some unrecognized force may be at play, but he's not sure what it could be.

"Maternal sentiments are not as compelling as they are commonly reputed to be," Wolf says. "We have to take seriously the possibility that they're not innate."

MOTHER NURTURE An old margarine commercial whimsically noted that it's not nice to fool with Mother Nature. Wolf agrees. When he went to Taiwan, he had no intention of toppling the current scientific thinking about innate maternal sentiments.

The Asian island initially appealed to Wolf as a natural laboratory for testing a biological theory of the incest taboo. Proposed more than 80 years ago by Finnish sociologist Edward Westermarck, the theory states that infants raised together would find it difficult to form sexual feelings for one another as adults, regardless of their genetic relationship. Natural selection preserved this innate response, Westermarck argued, because it guards against incestuous couplings, which increase the odds of defective offspring.

Minor marriages, which were popular in the 19th century and the first half of the 20th century in parts of southern China and Taiwan, offered a way to determine whether Westermarck was correct. Consistent with the incest-taboo theory, Wolf found that married couples in Taiwan who had grown up in the same families as the result of minor marriages reported few erotic feelings for one another and produced 30 to 40 percent fewer offspring than other married couples did.

Next, Wolf decided to explore another of Westermarck's conjectures: The dangers of infancy have, through natural selection, yielded an innate tendency in women to care for any infant with whom they come into contact for a prolonged period. Westermarck's argument anticipated the rise of what became known as attachment theory.

Now, social scientists theorize that new mothers typically experience hormonal and brain changes that sensitize them to their babies' needs. Infant's clinging and smiling then presumably reinforce the mother-child bond. In short, women are biologically disposed to develop maternal sentiments and suffer grievously if separated from any child whom they have raised for more than a few days.

To Wolf's surprise, his data challenged that bedrock assumption. In Taiwan 50 to 100 years ago, he contends, practical considerations about the future economic health of their households, not to mention their own social status, prompted women to give away daughters that they had raised for months or years.

It wasn't a case of poverty-stricken laborers and farmers being forced to part with beloved daughters because they couldn't afford to keep them. Wealthy families--those of rural landlords, shopkeepers, and others who paid a substantial land tax--gave away daughters at the same rate as poor families did, Wolf says. Using land-tax records for the communities where minor marriage was common, he found that by age 15, about two-thirds both of the 2,862 girls born into especially poor families and of the 467 girls born into well-off families had been adopted.

Neither the women's parents nor parents-in-law forced the mothers to dispose of daughters, Wolf argues. As senior family members, grandparents in these Asian cultures had the right to treat grandchildren as resources to be deployed in the family's best interests. But Wolf found that women gave up daughters for adoption as frequently when grandparents were absent, because of death or family division, as when they were living in the household.

Husbands could also have determined the fates of their children, but they typically delegated this authority to their wives. Women reported that they tank charge of adoptions and minor marriages, almost always acting as the go-betweens who transferred children from one family to another.

Minor marriage itself didn't perpetuate a mindset that fostered the practice, as could have happened if depriving girls of parental love while young had made it hard for them as adults to forge emotional bonds with their children. Minor marriages, Wolf reports, occurred as often among the 2,776 girls born to mothers who had not been adopted themselves as they did among the 3,425 girls born to mothers who had themselves been given up for adoption--nearly half as infants and 70 percent by age 15.

Still, by their own accounts, many women who had been adopted for minor marriages hated their mothers for having given them away, Wolf says. They reported that they had often been mistreated in their new homes.

Around 1930, northern Taiwanese women began to raise the majority of their daughters, and the demand for "little daughters-in-law" receded, Wolf notes. Young people had long complained about being pushed together too early in minor marriages, and social changes, such as expanded primary education and wage-paying job opportunities, that followed Japanese occupation a generation earlier, had greatly eroded parents' authority over their children, Wolf says.

TIES THAT BOND In the realm of lost mother love, Taiwan isn't unique. From the Middle Ages to the mid-19th century, "European women also gave their children away with no more--it seems to me even less--reason" than Taiwanese did, Wolf holds.

Historical documents and travelers' accounts describe a popular northern European practice of sending boys and girls, at about age 7, to live in other people's houses to perform menial labor as apprentices until adulthood. In many European cities, women--and not just aristocrats--often sent their babies and young children to be raised in foundling hospitals or by wet nurses in the country. This practice may have been more likely for mothers who never provided significant child care and who therefore may have left their maternal sentiments untapped, Wolf conjectures.

In contrast, the Taiwanese evidence shows that women who did nurse and protect their daughters for at least several months still gave them away. If a mother's love for a daughter had kicked in, it usually wasn't strong enough to outweigh her practical concerns.

Wolf's take on the limits of motherly love has attracted skepticism. Cross-cultural studies indicate that most women harbor a fundamental desire to protect their children, says psychologist Carol George of Mills College in Oakland, Calif. That propensity, sculpted by natural selection, is flexible enough to be suppressed in times of duress or threat when a woman is convinced that she's powerless to protect her babies, George proposes.

Mothers who have limited resources and also regard a child as extremely difficult to raise or unlikely to produce grandchildren--because of factors such as illness--are most likely to resort to adoption, child abuse, and even child killing, George theorizes.

Fears about their families' economic futures and the loss of influence over their sons, she says, could have caused Taiwanese mothers to conceal or suppress maternal sentiments for daughters they had cared for.

In Wolf's Taiwan sample, in-laws of childbearing women might also have been the ones orchestrating the minor marriages, contends Min-Tao Hsu of Taiwan's Kaohsiung Medical School. She has interviewed many elderly women who spoke of having resigned themselves to giving away daughters whom they loved because of incessant pressures from in-laws. It was, as some of these mothers told Hsu, "the choice of no choice."

It's also possible that Wolf documented a misguided caregiving strategy that evaporated in Taiwan because it wasn't "evolutionarily sensible," comments psychologist Jude Cassidy of the University of Maryland in College Park. A system of minor marriages that reduced couples' fertility by causing them to think of each other as siblings may have simply been a short-lived oddity, she says.

Wolf doubts that view. But even if it's true, he says, the Taiwanese data unveil the surprising fragility of maternal sentiments when, as rarely happens, a society encourages women to opt out of raising their unwanted children and provides an easy way to do so.

The provocative possibility arises that, in most societies, women adopt positive maternal attitudes only after reining in negative feelings about the demanding babies that everyone expects them to raise, Wolf suggests. After a while, the loving feeling for a child stoked by this maternal cognitive dissonance seems completely natural. "Having discovered that the children they suffered to bear are burdensome, women may have little choice but to love them or kill them," he says.

That's not a sentiment likely to show up on any Mother's Day card. Wolf would settle for inspiring a few more unflinching studies of motherhood in the wild.