Members of the Standing Committee of the National People's Congress (NPC) called on Saturday for a new criminal law prohibiting gender-based abortion and fetal gender identification for non-medical purposes.

"The gender imbalance will affect marriages for a certain period in the future and add to social instability," Standing Committee member Xu Zhihong said at the discussion.

Selective abortion also harms the health of women and in the majority of cases tragically ends the lives of female fetuses, said Xu, who is also president of Peking University.

Traditionally, Chinese people preferred sons since they were better able to provide for their families and support elderly parents. They were also believed to be the ones to carry on the family line. The tradition lingers, particularly in some rural areas.

Since the country's family planning policy allows most couples to have just one child, the persistent bias for boys sometimes leads them to decide to abort a female fetus. Others give birth but abandon the girl infants.

The national birth gender ratio has risen to about 117 boys to 100 girls, compared to 108 boys to 100 girls in 1982.

Although the practice of conducting ultrasound scans and telling the parents a child's sex is prohibited by regulation, many clinics accept payments to do so anyway.

The lawmakers are now considering whether to impose criminal penalties instead of the administrative sanctions and fines to which violators are now subject. The only criminal punishment now in place concerns people who have no medical license but conduct abortions.

More than 10 of the NPC Standing Committee members have proposed adding a criminal article targeting licensed doctors who reveal the sex of fetuses or conduct abortions for non-medical purposes.

But some are more cautious. "Revealing the sex of a fetus is against professional ethics but it alone is not up to the level of criminal offense," said Qiu Xinglong, a law professor at Xiangtan University, in the central province of Hunan.

He believes that identification should be punishable only when it leads to selective abortion.

"Having a rule to deter abortion is no problem, but where to draw the line is an issue lawmakers need to tread carefully."