Speaking at a recent population conference Nguyen Quynh Anh of the UN Population Fund said Vietnam is still heavily influenced by Confucian values, including patriarchy, which favors males over females in family matters and social settings.

Men are responsible for carrying on their family's lineage and worshipping their ancestors, among others, she pointed out.

"These concepts have been there for a long time and are passed down from one generation to the next, which in time form concrete gender roles, what each gender is capable of and the jobs they can partake."

She stressed that such prejudices are the fundamental source of gender imbalance in Vietnam.

Globally, women’s incomes are 50-90 percent of men’s, while in Vietnam, especially in the countryside, it is only 20-40 percent, she said.

The country also has the lowest ratio of women in top management out of Southeast Asia’s five biggest economies, according to a Financial Times survey last year, with one woman to every eight men compared with 5.6 in Malaysia, 2.8 in the Philippines and 2.2 in Thailand.

The sex ratio has been steadily leaning towards males in Vietnam, from 111.7 boys for every 100 girls born in 2017 to 115.1 boys for every 100 girls born in 2018, according to official statistics. 

As many as 4.3 million Vietnamese men are likely to remain lifelong bachelors in the next 30 years, Mai Xuan Phuong, a senior official at the Ministry of Health’s population and family planning department, had said in 2016.

The government is now encouraging families to have two children, instead of "a maximum two children" as before, as it faces a gender imbalance and has an aging population.