Daughters are useless and unworthy!” shouted an elderly woman in a village near Busan in South Korea in 1996. Other old women sitting with her, as we talked about families, nodded their agreement. Why, I asked? It was not because daughters were lazy, she said. “No, women did a lot of hard labor in the fields, and their marriage costs virtually nothing. People don't want daughters, because they are not helpful to the family—they leave the family when they marry. It is sons who stay home, inherit assets and keep the rituals of ancestor worship.”

In China, I heard similar stories. A man said that when his daughter was born, “my wife was so upset that she did not want to care for the child, and I had to persuade her to nurse it.”

These attitudes have had life-and-death effects. The natural human male-female birth ratio is only about 5 to 6 percent more boys than girls. But in China in 2000, there were 20 percent more boys born. This kind of skewed sex ratio has been found across much of East Asia, South Asia, the southern Caucasus and parts of the Balkans. Female babies are aborted in these areas, killed at birth or die through neglect. Why? As the woman from Busan said, it is brutal economics. These cultures have historically excluded adult daughters from helping in their parents' households or inheriting property, which diminishes their value to their birth family.

But recently the demographic bias against females has begun to shift. South Korea has shown a rebalancing of child sex ratios since the mid-1990s, with proportions of boys to girls dropping from high levels to biologically normal ones. There is even a shift toward a preference for daughters in South Korea today. In India, the 2011 census shows a sharp drop in sex ratios in children in the northwestern part of the country, where they had been very high. In China, the climb in such sex ratios has leveled off.

These shifts coincide with rapid urbanization and social changes that have helped make daughters more valuable to their parents. Daughters no longer vanish from their birth families, and in some cases, they bring in additional men from outside. Twenty years after my original fieldwork in Busan, one woman in South Korea told me, “My mother suffered a lot of abuse when she was young because she had three daughters and no sons. Now that we are grown, she is very happy because we all remain close to her. She says that her sons-in-law treat her better than sons.”

Shoving Women Out

For centuries the social organization of rural society in China, South Korea and northwestern India pushed daughters away from their parents' households. When women married, they were absorbed into their husband's family. New labor in their birth family was provided by daughters-in-law marrying in, further emphasizing the value of sons. A similar social structure appears in other regions with strong son preference, including northern Vietnam and the southern Caucasus countries.

To cement this daughter transfer, when a woman joins her husband's family, her “slot” in her birth family is eliminated. A new slot is created for incoming brides. If women do return—a rare occurrence—they and their parents have to struggle hard to make the unusual situation work. Other members of the family and the village resist because of the potential reduction of their property rights. Once a woman from rural China has been married and her land entitlement reallocated among village residents, for example, her return can be met with a fair amount of antagonism.

Credit: Jen Christiansen; Sources: “'Missing Girls' in China and India: Trends and Policy Challenges,” by Guo Zhen, Monica Das Gupta and Li Shuzhou, in Asian Population Studies, Vol. 12, No. 2. Published Online June 6, 2016 (children in India, ages 0–6, and children in South Korea and China, ages 0–4); National Census Data (China, India, South Korea); World Population Prospects: The 2017 Revision. DVD Edition. Population Division, Department of Economic and Social Affairs, United Nations. United Nations, 2017 (North America, Western Europe, Northern Europe)

The impact of these cultural norms can be seen in the contrast between elder living arrangements in countries such as Taiwan and South Korea and those in countries such as the Philippines. The first two have rigidly patrilineal (male-oriented) kinship systems, whereas the third has a system of kinship that does not favor children of any one gender. In Taiwan and South Korea, a substantial proportion of parents live with married sons, but almost none live with married daughters, according to a forthcoming study I conducted with Doo-Sub Kim of Hanyang University in Seoul. In the Philippines, parents are equally likely to live with married children of either gender. It is not surprising that child sex ratios are normal in the Philippines but have been lopsided in Taiwan and South Korea.

The results of devaluation of females are not surprising, either. Unwanted girls have been removed through infanticide and neglect, producing male-skewed child sex ratios. Beginning in the 1980s, sonograms and other technologies for prenatal sex detection made it possible to act on sex bias even before birth. The new methods made it easier for parents to avoid having unwanted daughters—through abortion—and sex ratios at birth showed more imbalance.

Major disruptions such as famine and war heighten the pressure on parents to get rid of children they perceive to be superfluous. Beginning in 1937, Japanese troops swept through eastern China, and girls went “missing:” 17 percent more girls died than one would expect from typical mortality rates in this situation. Parents in war-torn regions felt that they had to make some harsh choices. A woman in the province of Zhejiang told me of her own experience in the 1930s: “When I was six years old, my mother said that I should be sold. I begged my father not to do this, that I would eat very little if only they would let me stay at home.” The collapse of governmental institutions can have similar effects. In the southern Caucasus countries, for instance, birth ratios favoring boys shot up when the U.S.S.R. was dissolved.

A shift from large to small family size also increases the pressure on parents to select for sons. In large-family, high-fertility settings, parents can afford to have several daughters and still go on to have one or two sons. In small families with fewer births, there are only limited chances to have sons. The second girl born into such families in son-favoring cultures has a much higher chance of dying before birth or during early childhood.

When Brides Are in Short Supply

The deaths of these female babies are a shocking result of gender inequality. The damaging effects ripple through society. Eventually they translate into a shortage of adult women. And after heightened periods of sex selection in earlier decades, a “marriage squeeze” now grips China, South Korea and northwestern India. China presents the starkest scenario. In 2010 the Chinese Academy of Social Sciences estimated that by 2020, one in five men in China will be unable to find a wife.

The bride shortage affects poorer men most severely. In China, Shang-Jin Wei of Columbia University and his colleague report that poorer parents in areas with imbalanced sex ratios struggle to improve their sons' chances in the marriage market. The parents resort to desperate measures such as taking on dangerous work to earn more and build a nicer house, one that can attract this newly scarce and valuable commodity: a bride to marry into the family.

Credit: Jen Christiansen; Source: “Gender Bias in China, South Korea and India 1920–1990: Effects of War, Famine and Fertility Decline,” by Monica Das Gupta and Li Shuzhou, in Development and Change, Vol. 30, No. 3; July 1999

At the same time, the marriage squeeze can benefit women. In areas of China with fewer potential brides, a study by Maria Porter of Michigan State University found that women have greater bargaining power within their marriage, enabling them to provide greater support for their parents than before. Women from poor areas can marry men who offer higher living standards, either locally or by migrating to other parts of their country. Some migrate to other countries to marry better-off men. In China, South Korea and India, several studies show these long-distance suitors are typically socioeconomically disadvantaged compared with other men in their own locale. They are unable to attract a local wife but still can offer an improved standard of living to women from impoverished regions.

These migration marriages do come with risks for women, however. Some research suggests that women who come from different ethnic or linguistic groups face problems in assimilation, are viewed as outsiders, do not know the local language and customs, and have limited social networks in their new setting. Many such marriages are to men who live in rural areas, and rural life further isolates the brides.

Difficulties can go beyond social isolation and cultural misunderstandings. In a 2010 study of Vietnamese brides in Taiwan, done by researchers at Viet Nam National University, Ho Chi Minh City, most women said that they were happy because they were able to help their birth families financially. But some mentioned problems, such as being humiliated by their husband and in-laws for their poverty, suffering domestic violence or being made to work like a slave. In Taiwan, in fact, a 2006 study found that marriage migration was a risk factor in domestic violence. And in South Korea, Hanyang's Kim found a greater likelihood of divorce among such marriages.

Some researchers and policy makers have also suggested that the creation of a generation of enforced bachelors may raise levels of crime and violence, including violence against women. Crime levels climbed in areas with higher male-to-female ratios, according to a study in India led by Jean Drèze, now at the University of Allahabad, as well as another study, which was conducted in China by Lena Edlund of Columbia and her colleagues.

The Value of Women

Over the past two decades the bias against girls has begun to diminish. My colleague Woojin Chung and I documented this phenomenon in a study of South Korean women's changing attitudes toward children's gender. When interviewed in 1991, 35 percent of women born between 1955 and 1964 said that they “must have a son.” But by 2003, only 19 percent of women born in that same period held this view. Changes in attitude have swept across society. Even after accounting for differences in education levels and urban versus rural residence, the odds of women aged 15 to 49 stating they “must have a son” in 2003 were roughly one third of the 1991 level. Changes in social norms account for as much as 73 percent of this decline. Only 27 percent of the drop is caused solely by increases in individual levels of education and urbanization. When attitudes changed, child sex ratios followed, as shown in the box on the opposite page.

What turned the corner, enhancing girls' value? It is a hard answer to tease out, but the increasing urbanization and education of parents play a major role. South Korea, for example, has urbanized at blistering speed, with the percentage of people living in and around cities doubling between 1966 and 1986, from 33 to 67 percent. By 1991, 75 percent of the population lived in urban areas. The effects of urban life on son preference are both social and economic. Living in a city reduces the centrality of sons' roles in their parents' lives. While villagers spend their days surrounded by clan members, urban residents live and work in the more impersonal settings of apartment blocks and office complexes. This shift relieves pressure to conform to traditional expectations of filial duty and to have sons to continue the lineage.

Credit: Jen Christiansen; Source: “The Decline of Son Preference in South Korea: The Roles of Development and Public Policy,” by Woojin Chung and Monica Das Gupta, in Population and Development Review, Vol. 33, No. 4: December 2007; National Census Data

In urban areas, children who support their parents tend to do so less because of formal rules and more because they happen to live in the same city and have strong relationships with their parents. In this way, urbanization helps to bridge the gap between the value placed on daughters and sons. Female education and employment also enhance the potential support they can offer. And with growing access to pensions and social protection systems, people become less dependent on their children for financial support.

Government policies have also nudged male preference into decline by encouraging mainstream equality for women. India has used affirmative action to increase women's political participation, putting a female quota in place for candidates for local government positions. Social scientists have found that after the policy was created, gender stereotypes weakened in the population as a whole, and girls' aspirations for themselves rose.

Extensive media outreach has also been a staple feature of family-planning programs in India, China and South Korea. Posters and commercials encourage parents to have small families even if they do not include sons. These efforts promote the view that daughters are just as good as sons for family happiness.

Female characters in popular Indian television soap operas now work outside the home and are active in public life. The values and roles illustrated in these programs challenge traditional views of a woman's place in society. Studies show that exposure to these messages is associated with reduced son preference.

There have also been direct attempts to change sex ratios by banning the use of technology for prenatal sex detection and selection. These bans have been put into place in several countries, but there has been little rigorous evaluation of the impact of these measures because of a lack of data. India's ban on sex selection appears to have had at most a modest effect. A vigorous effort in China to ban birth selection has shown little effect on the national sex ratio of babies.

Countries in Asia are still urbanizing rapidly, so I believe the preference for sons will continue to decline. Policy makers can accelerate this process through legal and other measures enhancing gender equity. They can also expand media advocacy and portray women helping their own aging parents (not just their in-laws). Such steps help to change gender stereotypes and overcome parents' preference for sons. For women—and for society in general—such approaches may have better outcomes than outright attempts to ban the selection of sex at birth.