Beijing

China's AIDS crisis could take a turn for the worse because of a surplus of men in the population, suggests a new study.

A paper published in this week's issue of the journal AIDS (19, 529–547; 2005) argues that an excess of boys in China's population could exacerbate the AIDS problem in cities. The sex bias is the result of the nation's ‘one-child’ policy and the fact that many parents want that child to be male.

The paper, “Surplus men, sex work, and the spread of HIV in China”, is authored by Joseph Tucker, a medical doctor in training at the University of North Carolina's Center for Infectious Diseases, and his co-workers. It says that there are now about 12 boys born for every 10 girls in China. The widespread availability of ultrasound techniques, which allow doctors to identify the sex of fetuses and give parents the ability to choose, is worsening the imbalance. Tucker argues that the resulting “surplus men” — which he calculates to be about 8.5 million — are likely to be unmarried, poor and lacking education.

The number of prostitutes in China has also skyrocketed: it has admitted that there are now between 4 million and 6 million, compared with only 25,000 in 1985.

Historical precedents, such as a sex-ratio imbalance caused by mass migration to Shanghai in the 1930s, have led to rampant sexually transmitted infections. Tucker, who spent a year working at a clinic for sexually transmitted diseases in Nanjing, says that another such situation could be developing.

Until now, consideration of the HIV problem in China has often focused on isolated communities, such as intravenous drug users or the victims of contaminated blood banks. But sexual transmission is playing an increasing role and some fear it will lead to an urban explosion of AIDS.

Some epidemiologists and HIV experts have challenged the speculative nature of Tucker's argument, however. Terry Hull, a social demographer at the Australian National University, Canberra, questions the idea that “poor unemployed migrant males” will be fertile ground for HIV transmission. “We might as easily argue that they will also ignore safety messages on the job and have more occupational deaths,” he says.

Tucker admits that his theory is only a hypothesis. But he hopes it will focus more attention on a possible seed of disaster. He calls for more education at construction sites, military areas and unemployment centres, where the surplus males gather. “These boys are coming of age,” he says.