Experts are calling for enhanced childhood screening of birth defects that cause partial and complete hearing loss with the hope that earlier detection will lead to better treatment.

More than 800,000 children under the age of 6 in China have hearing problems, and about 60 percent are due to genetics, said Han Demin, a World Health Organization's hearing expert.

In 2009, the Biochip Research and Development Center of Tsinghua University developed the world's first DNA test for birth defects that affect hearing. Free screening has benefited about 700,000 children for free in Beijing over the past three years, but it is not yet common nationwide.

"Based on the gene test through biochips, hearing problems resulting from gene defects can be detected at an early stage," said Cheng Jing, director of biochip center.

The test also provides clues on preventing the transfer of affected genes to the next generation, the WHO's Han said.

"With timely treatment, many children can still build a good speaking ability," Han said at the opening ceremony of the China Audiology Forum 2015 today in Beijing.

Gene tests for adults are currently available at three Beijing hospitals: Beijing Tongren Hospital, Peking University Third Hospital and The General Hospital of the People's Liberation Army. It costs about 800 to 900 yuan per person.

Cheng said the center is contacting health officials in some districts and counties in Beijing with thoughts of expanding such screening..

"A pilot project might be launched to provide gene tests for hearing defects as part of a health check before marriage," Cheng said.