BEIJING, Jan. 23 -- East China's Anhui became the third province to relax the decades-old one-child policy on Thursday, allowing couples to have a second baby if either parent is an only child.

About one week earlier, the neighbouring province of Zhejiang took the lead in the country to relax the strict family planning rules. Jiangxi Province followed suit on Jan.18.

"The policy change comes just in time," said Shen Xian, a 35-year-old woman from Liuyuan Village under Shangrao County, Jiangxi.

"My husband is from a one-child family and I don't want my son to be a lonely only child," said Shen, who is brought up under the traditional Chinese belief that happiness lies in having many children.

Shen was banned to have a second child under the previous provincial policy.

The relaxation means a significant change to the family-planning policy that has been in effect for more than three decades across the country. The move is a part of a plan to raise fertility rates and ease financial burden on China's rapidly ageing population.

Provincial-level governments in Beijing, Guangxi, Hubei and Jiangsu have announced their intentions to relax the policy in March. Others, including Hunan, Qinghai and Shanghai, promised changes in the first half of this year.

Following the rapid economic growth in the past decade, China's population advantage has shrunk. China has become an aging society with too few young working people supporting parents and grandparents. For years, experts from many walks of life have been calling for the relaxation of the policy.

China's family planning policy, put in place in the late 1970s, is designed to curb population growth. It has been widely believed to contribute to the country's rising prosperity.

Under the scheme, most couples are allowed to have only one child, except for rural families with only a girl, or ethnic minority couples both of whom are only child.

The policy has been strictly enforced with heavy fines on those breaking the rule. Under a local court decision, famous film director Zhang Yimou will pay a fine of 7.48 million yuan (1.22 million U.S. dollars) for having three children, according to the family planning bureau of Wuxi City in east China's Jiangsu Province earlier this month.

It is estimated that the one-child policy has so far prevented around 400 million people from being added to China's population, which stands at 1.34 billion today.

Some also argue that the one-child policy has contributed to gender imbalance in China, where sex-specific abortions remain common in a culture that prefers boys over girls.

The gender ratio at birth was 117.60 (117.60 boys vs 100 girls) in 2013. A ratio between 100 and 107 is considered normal.

Having noticed the policy flaws, the Communist Party of China (CPC) Central Committee decided to adjust the policy in November 2013. The Standing Committee of the National People's Congress, the top legislature, approved the decision in December, leaving provincial congresses and their standing committees to make their own calls on implementation. A number of local congresses have since started revisions.

Adaptation of the birth-control rules acknowledges the real situation on the ground in China, just as the level of economic development and demographic composition are diversified across the country, said Lu Jiehua, professor of the Institute of Population Research, Peking University.

Decreasing fertility rates and the problem of insufficient young people have become more acute in developed eastern regions, so it is reasonable for them to take the lead, said Zhang Chewei, deputy head of the Population and Labor Economics Research Institute with the Chinese Academy of Social Sciences.

Zhejiang is one of the wealthiest provinces and a major manufacturing powerhouse in the country. A labor shortage looms as the population ages.

In general, the average fertility rate stands at 1.5 births per woman in China. This is not enough to offset aging. A working population shrinks when the fertility rate is lower than 2.1, experts say.

In Henan and Guangdong provinces, each with a population over 100 million, local governments have taken a more prudent approach with no timetable for implementation.

For a relatively underdeveloped province of a large population, changes to the birth-control policy should be made cautiously and only after thorough investigation and calculation, said Wang Jieying, spokesperson for the Henan provincial health and family planning commission.

"We have to take full account of population trends and extra pressure on public resources, including food, health, education and employment," said Wang.

There would be 50,000 to 80,000 more babies every year in Henan, if the new regime takes effect, according to an initial calculation by the commission.

Relaxation is likely to bring a mini baby boom in the province but the commission believes its impact will be manageable.

Guangdong has sent a report on the matter of adjustment to the National Health and Family Planning Commission. If the report is approved, a policy adjustment will be made when the provincial congress revises current regulations.

"We are actively seeking early approval from the central government and will make the changes as soon as possible," said Chen Yuansheng, head of the Guangdong health and family planning commission.

"The effect on education, health and employment will be minimal," said Chen. Guangdong is the most developed province in China with a gross domestic product of more than 1 trillion U.S. dollars.

Many Chinese women have expressed limited interest in having second children, so these changes will not lead to unexpected population growth and serious social problems, said Zhang Chewei.

The rising cost of living and housing prices in cities and children education expenses have forced many young parents to give up the idea of raising a second child. In the countryside, many prefer less offspring for the prospect of their children.

Many would envy Shen Xian, who runs a chicken farm that yielded a family income of 100,000 yuan in 2013, enough feed two kids with dignity. Farmers in Jiangxi had an average yearly income of 7,828 yuan in 2012.

China's fertility rate, 3.34 percent in 1970, fell to 1.21 percent in 2012. Population growth dropped from 2.58 percent to 0.495 percent in the same period, according to health authorities.

In an open letter on birth control to members in 1980, the CPC Central Committee was visionary in predicting a different population panorama in China three decades later.

"Thirty years from now, the current tense population growth problem will have eased and we can adopt a different approach to birth control," reads the letter.

"The Chinese government has kept its promise 33 years on," said Lu Jiehua.