Sex, society and suspicious minds

DNA paternity tests are becoming increasingly popular in China as marital ties loosen.

Since China initiated the opening-up and reform policy in the late 1970s, the country has changed beyond recognition, economically, socially and sexually. While millions of people have been lifted out of poverty as the country has grown to become the world's second-largest economy, the rise in living standards has also resulted in greater sexual freedom and a more tolerant society.

This has been great news for people such as Deng Yajun. Her working day involves dealing with one of the great secrets of the human body: the genes and the unique coding mechanism that distinguishes us from one another, but also provides links between families. Deng conducts DNA tests.

In the past 10 years, her team at the Zhongzheng Forensic Authentication Institute in Beijing has tested more than 50,000 DNA samples, more than 40,000 of them for paternity tests. The technology, which has been in use in China since the 1990s, has seen a rise in popularity during the past decade, partly because rising standards of living mean more people can afford to use it and also because the number of extramarital affairs has risen in China's rapidly developing society.

Suspicious husbands intent on finding out if their wife has been unfaithful have provided strands of hair, fingernail fragments and even discarded baby teeth. Sometimes, anonymous requests are sent to the labs via express messenger services.

"Anonymous requests account for 60 percent of all DNA paternity tests," said Deng, 42, whose institute has seen the demand for tests rise by 15 to 20 percent since 2000.

The introduction of high-tech equipment means conducting a paternity test has become far easier and is now more accurate than ever, according to Deng. A simple test costs from 2,400 to 3,600 yuan ($385 to $579) and the results are available within two weeks.

The number of tests has increased more rapidly in prosperous zones, such as South China's Guangdong Province, including the cities of Guangzhou and the manufacturing hub of Shenzhen. Local news reports indicate that the People's Hospital in Shenzhen, which neighbors Hong Kong, has seen an annual 50 percent rise in the number of paternity tests since 2000.