China, worried about an ageing population, is studying scrapping its controversial one-child policy but will not do away with family-planning policies altogether, a senior official said on Thursday.

With the world’s biggest population straining scarce land, water and energy resources, China has enforced rules to restrict family size since the 1970s. Rules vary but usually limit families to one child, or two in the countryside.

“We want incrementally to have this change,” Vice Minister of the National Population and Family Planning Commission Zhao Baige told reporters in Beijing.

“I cannot answer at what time or how, but this has become a big issue among decision makers,” Zhao said. She added that the current plan was to study the issue seriously and responsibly, but avoid sudden changes that might cause a spike in births.

“Minority groups already have two children, even three, and in the cities like Shanghai and Beijing, a lot of only children are already released (to have two), but the most important is those in the middle like in Henan… nearly a hundred million people, but strongly influenced by the classical way, they want a son, and they are already very fragile environmentally.”

Teams studying the issue would have to consider the strain of China’s huge population on its scarce resources, popular attitudes, and how much of a social net China can afford to provide without the traditional reliance on large families to care for the aged, she said.

Surveys show that 60 percent of Chinese younger than 30 want a maximum of two children, and only a “very small” number want more than three, Zhao said.

The average number of children that would be born to a woman over her lifetime has decreased to 1.8 in China today, from 5.8 in the 1970s, and below the replacement rate of 2.1.

RELAXATION

In recent years, China has sought to soften its draconian and often controversial family control policies, which have included forced abortions and other punitive measures.

But local officials remain under intense pressure to keep numbers down, leading to skewed statistics and sometimes brutality.

The country is now relying more on education, especially about contraception, said Zhao, in charge of international cooperation, education and communication at the ministry.

China says its policies have prevented several hundred million births and boosted prosperity, but experts have warned of a looming social time-bomb from an ageing population and widening gender disparity stemming from a traditional preference for boys.

Normally, between 103 and 107 boys are born for every 100 girl infants, but in China, 118 boys are born for every 100 girls, Zhao said. Experimental policies include trying to improve women’s welfare and girls’ access to schooling.

Still, the government has previously expressed concern that too many people are flouting the rules.

State media said in December that China’s population would grow to 1.5 billion people by 2033, with birth rates set to soar over the next five years.

Officials have also cautioned that population controls are being unraveled by the increased mobility of China’s 150 million-odd migrant workers, who travel from poor rural areas to work in more affluent eastern cities.

China has vowed to slap heavier fines on wealthy citizens who flout family planning laws, in response to the emergence of an upper class willing to pay standard fines to have more children.