Asia's missing girls: a traditional preference for boys, combined with technology that allows pregnant women to know the sex of their babies, has led to a huge gender imbalance in China and India.

• Author: Smith, Patricia
• Position: INTERNATIONAL

Yang Xiaowei, a 35-year-old chicken farmer from a village in eastern China, has three children: two older daughters and a long-awaited baby boy.

Having a son is so important, Yang explains, that he and his wife were willing to risk the large fine that could result from violating the government's one-child policy.

"If you don't have a son, people will condescend to you," he says. "It's always been this way. If you have a son, your family will be given a certain social status. You can ask 10 people in the village, and they'll all tell you the same thing."

This kind of thinking is at the heart of a massive demographic problem facing China. Until recently, there wasn't much that anyone could do about having sons or daughters. But in the 1980s, ultrasound scanners--which were intended for checking the health of developing fetuses but also can show their sex--became widely available across Asia.

Suddenly it became easy for women to find out if they were going to have a boy or a girl. And in countries like China and India, women began deciding not to have their baby if it was going to be a girl. The result is a serious gender imbalance in both countries.

China now has the world's highest gender disparity among newborns: 119 boys are born for every 100 girls. That's well above the natural ratio of 105 boys for every 100 girls (which is also the ratio in the United States). In some parts of China and India, the imbalance is close to three boys for every two gifts. Across Asia, the gender imbalance translates into millions of "missing" girls.

Within a decade, that will mean millions of young men unable to find wives. And experts fear that could lead to an increase in the trafficking of women and an overall spike in crime.

"It's a humongous problem," says Valerie Hudson, a professor at Brigham Young University in Provo, Utah, and coauthor of a book on the topic. "Without a balanced sex ratio in a society, you're courting disaster."

Beyond Asia

Worldwide, demographers say, the number of missing girls has risen to more than 160 million. The problem is most severe in China, India, and the Caucasus region, which includes Azerbaijan, Armenia, and Georgia (see chart). But sex ratios are also out of balance in other places, including parts of Europe and Asian-American communities in the United States.

"We've seen sex selection spread from South and East Asia to new countries, and that's alarming," says Mara Hvistendahl, author of Unnatural Selection: Choosing Boys Over Girls, and the Consequences of a World Full of Men.

"The preference for sons is very widespread," she adds.

In China, the problem is partially a result of the country's tough one-child policy. It was introduced in 1979 as an attempt to stem the growth of China's population, which is...