( CNN ) -- The world 's population is expected to hit 7 billion around October 31 and one Chinese demographer says that number would have come a lot sooner had it not been for China 's `` one-child policy . '' Zhai Zhenwu , a professor at Renmin University School of Sociology and Population , says but for China 's population policy , the world 's 7 billionth baby would have been born five years earlier . `` China 's population would now be around 1.7 billion had it not been for the family planning policy , '' said Zhai . `` And the world 's population would have hit seven billion in 2006 . '' China holds the largest population on earth with 1.34 billion people , but will not for long , as the fertility level has been declining for years . Since the Chinese government adopted its so-called `` family planning policy '' three decades ago , China has limited couples to one child , with few exceptions . Those who broke the rule were slapped with heavy fines or were forced to abort pregnancies . Since 1979 , experts at the National Population and Family Planning Commission of China say , the policy has prevented more than 400 million births in the country . Why was the draconian policy necessary ? Proponents rationalized it as an emergency measure to curb the large number of births expected from the baby boomers of the 1960s . `` It was designed in 1979 to be a temporary one that required the 'sacrifice of two or three generations , ' as they put it then , '' says Aprodicio Laquian , who served as the United Nations Fund for Population Activities ( UNFPA ) representative and senior adviser on population in China from 1984 to 1990 . `` It was meant to be implemented until the annual population growth rate reached replacement levels , or 1.5 children per woman of reproductive age . '' The Canadian demographer says supporters of the policy now cite the double-digit economic growth rate since 1979 as the so-called `` demographic dividend . '' Laquian explains : `` If population control had not been enforced , China would most likely be economically and socially worse off today . '' The population policy might have also helped girls and women get ahead , as a survey by the All-China Women 's Federation and the National Bureau of Statistics found . But the policy has also brought about a list of unintended socio-economic consequences . China 's one-child policy has been blamed for abuses , including female infanticide and forced abortions and sterilizations . Chinese traditionally prefer boys over girls because they are seen as more able to provide for the family and carry on the family line . As a result , the practice of aborting female fetuses or abandoning infant girls still continues today in rural areas . This remains a sensitive topic in China , poignantly depicted in Mo Yan 's `` Frog , '' a novel about a midwife in rural China and her experiences with forced abortions and sterilizations . Mo recently won China 's prestigious Mao Dun literary award -- a potential indication that China has become more open to talking about the issue . China is now facing a lopsided sex ratio in infants and young children . According to the Chinese Academy of Social Sciences , for every 100 Chinese girls born , there are about 123 boys . The global norm is about 100 to 103-106 . At that rate , China is likely to have some 30 million unmarried men by 2020 . The unusually rapid decline in fertility has also produced a rapidly aging population . Two decades ago , demographers say , the share of China 's population aged 60 and above was only 7.6 % . That has risen to 10.5 % , according to China 's 2000 census , and has now reached around 12 % , or 167 million . By 2025 , demographers predict , one in five Chinese who live in urban areas will be 60 or older . By 2050 , there would be only 1.6 working-age adults for every person aged 60 and above . That means a heavy dependency ratio . In 10 years , the 20-24 age population is expected to comprise of only half of today 's 124 million . Experts say this could cripple the health care and social insurance system with fewer young people taking care of the aging population . If the government does not change its policies , experts say , China 's population could become old before it becomes rich . The high cost of the one-child policy is felt deeply by Beijing resident Xiao Xuan , an only-child daughter of a college professor and shopping mall manager . Xiao , 22 , says she was blessed with all the attention and resources showered at her from childhood . Still , she says , she had a mostly lonely childhood . `` I used to cut myself on my wrist after being yelled at by my mom and dad because I did n't know who I should talk to or turn to , '' she says . `` I was like that for almost two years , but I am very tough so I made it through . '' `` I hate to say it but the one-child policy should partly be blamed for some social issues of youth today , '' she adds . `` It 's been a ridiculous government interference on family issues . '' She wished she had a brother or a sister to share all the attention . `` I am the only one there , so all their energy goes to me , '' she says . `` They care of no one else but me , and live vicariously through me , because they can count on no one else . Parents ' love could multiply if there are more kids in the family , but if you are the only one , you get only one piece of cake , not a whole bakery . '' Canadian demographer Aprodicio Laquian says the Chinese authorities are aware of these unintended consequences of their population policies and are committed to dealing with the situation . `` It is anticipated that China 's strict population control program will most likely be relaxed as the objective situation changes , '' he said . For Xiao Xuan 's parents , however , such a relaxation of policy may come too late . `` My parents have often expressed regret , '' she says . `` They said they should have had another kid regardless of how much the [ government ] fined back then . ''
If not for China 's one-child policy , world population would have hit 7 billion five years ago . Fertility rates in China , the world 's most populous nation , are declining . Supporters of the policy say it helped spur China 's double-digit economic growth . Policy 's unintended consequences include female infanticide , lopsided sex ratio .