Vietnamese doctors who reveal the sex of a foetus to parents could lose their licences, state media reported on Saturday.
The proposal by the Ministry of Health is designed to address an imbalance in the number of boys to girls, said Duong Quoc Trong, deputy head of the General Department of Population and Family Planning. He was quoted by Vietnam News.
In May the United Nations Population Fund noted a steadily increasing sex ratio at birth in Vietnam. The ratio is now 112 boys born for every 100 girls, compared with a usual ratio of 105 or 106 boys without sex selection, it said.
Trong said it will not be easy to detect and punish doctors who reveal the sex of a foetus after an ultrasound, because they may just give the parents a verbal report and not make a written record.
"The reason behind the gender imbalance is parents' preference for having boys, who are likely to be family breadwinners," Trong said.
"So besides making an effort to change traditional beliefs it is important to increase women's role in society."
Men in Vietnam -- where abortion is widespread -- have traditionally carried on the family lineage, inherited homes and land, and cared for elderly parents as well as overseeing funerals and ancestor worship rituals.
Vietnam's prime minister has already prohibited all practices of foetal sex determination and selection, the UN noted.
"Furthermore, continued efforts must be made to strengthen public education and to promote gender equality to enhance the important role of women both within families and society," the UN said.