The number of couples undergoing premarital examinations has been dropping drastically since the mandatory premarital examination policy was dropped in China in 2003.

The number remains low, although some cities later began to offer free premarital examinations.

Xu also urged the government to boost support to the families of babies with serious birth defects to prevent them from abandoning the baby.

The treatment of a baby with serious heart disease at the Guangzhou welfare home for children, for example, costs 300,000 yuan (US$43,926), which is totally beyond the reach of poor families.

After a 3-year-old boy with serious complications from the H1N1 flu was found dead and abandoned in Guangzhou last December, a spokesman for the Guangzhou health bureau said more efforts are needed from all of society to help the financially disadvantaged patients, especially those from outside the city.

The city government of Guangzhou set aside some money last year for hospitals to assist poor patients from outside the city, but the maximum help for a patient is 7,000 yuan, he said.

"Better social security would also help change the long-rooted tradition of relying on boys to support the family," Zeng said.

"That might help end gender discrimination."

The abandonment of babies born out of wedlock has increased due to an increase in cohabitation and migrant workers having sex outside of marriage, since they are away from their wives for long periods of time.

Premarital sex, which often involves unprotected sex, is prevalent among those born in the last three decades.

Providing knowledge about responsible sex and protection, including the use of condoms, is very important, he said.