<< Back To HomeCSU 56/2009: CHINA'S EXCESS MALES, SEX SELECTIVE ABORTION, AND ONE CHILD POLICY
| Printable Copy |
 |
CSU 56/2009: CHINA'S EXCESS MALES, SEX SELECTIVE ABORTION, AND ONE CHILD POLICY
In both China and India, ultrasound screening and selective abortion
of females is skewing sex ratios among children, adolescents and young
adults. What are the social repercussions of this practice?
Zhu and colleagues quantify the practice in this recent BMJ article.
Text, without tables and graphics, is at the foot of this E-mail. Full
text, with tables, is at
http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=19359290
From the summary:
What is already known on this topic
• The reported sex ratio (males per 100 females) in China is high, but
accurate population based figures for actual sex ratios have been
notoriously difficult to obtain
• The role of sex selective abortion and the influence of the one child
policy on the sex imbalance have been unclear
What this study adds
• China will see very high and steadily worsening sex ratios in the
reproductive age group for the next two decades
• Sex selective abortion accounts for almost all the excess males
• One particular variant of the one child policy leads to the highest sex
ratios
Good reading.
BD
To subscribe or unsubscribe from this list, pls contact Evelyn Chege,
echege@unicef.org.
Do not subscribe on behalf of friends or colleagues; forward updates to
them for their decision.
BMJ. 2009; 338: b1211.
Published online 2009 April 9. doi: 10.1136/bmj.b1211. PMCID: PMC2667570
Copyright © Zhu et al 2009
China’s excess males, sex selective abortion, and one child policy:
analysis of data from 2005 national intercensus survey
Wei Xing Zhu, professor,1 Li Lu, professor and head of department,2 and
Therese Hesketh, senior lecturer 3
1College of Law, Political Science and Public Administration, Zhejiang
Normal University, Jinhua, Zhejiang 310347, China
2Institute of Social and Family Medicine, Zhejiang University, Hangzhou
310016, China
3Centre for International Health and Development, University College
London, London WC1N 1EH
Corresponding author.
Correspondence to: T Hesketh Email: t.hesketh@ich.ucl.ac.uk
Accepted November 27, 2008.
This is an open-access article distributed under the terms of the Creative
Commons Attribution Non-commercial License, which permits unrestricted use,
distribution, and reproduction in any medium, provided the original work is
properly cited.
Abstract
Objectives To elucidate current trends and geographical patterns in the sex
ratio at birth and in the population aged under 20 in China and to
determine the roles played by sex selective abortion and the one child
policy.
Design Analysis of household based cross sectional population survey done
in November 2005.
Setting All of China’s 2861 counties.
Population 1% of the total population, selected to be broadly
representative of the total.
Main outcome measure Sex ratio defined as males per 100 females.
Results 4 764 512 people under the age of 20 were included. Overall sex
ratios were high across all age groups and residency types, but they were
highest in the 1-4 years age group, peaking at 126 (95% confidence interval
125 to 126) in rural areas. Six provinces had sex ratios of over 130 in the
1-4 age group. The sex ratio at birth was close to normal for first order
births but rose steeply for second order births, especially in rural areas,
where it reached 146 (143 to 149). Nine provinces had ratios of over 160
for second order births. The highest sex ratios were seen in provinces that
allow rural inhabitants a second child if the first is a girl. Sex
selective abortion accounts for almost all the excess males. One particular
variant of the one child policy, which allows a second child if the first
is a girl, leads to the highest sex ratios.
Conclusions In 2005 males under the age of 20 exceeded females by more than
32 million in China, and more than 1.1 million excess births of boys
occurred. China will see very high and steadily worsening sex ratios in the
reproductive age group over the next two decades. Enforcing the existing
ban on sex selective abortion could lead to normalisation of the ratios.
Introduction
In the absence of intervention, the sex ratio at birth is consistent across
populations at between 103 and 107 boys born for every 100 girls.1 2 Higher
early mortality among boys ensures a ratio of close to 100 in the all
important reproductive years. However, in many countries, mainly in South
and East Asia, the sex ratio deviates from this norm because of the
tradition of preference for sons.3 Historically, preference for sons has
been manifest postnatally through female infanticide and the neglect and
abandonment of girls.4 Where this persists, it mainly consists of failure
to access necessary medical care.5 6 However, since the early 1980s
selection for males prenatally with ultrasonographic sex determination and
sex selective abortion has been possible. This technology has become widely
available in many countries, leading to high sex ratios from birth.5 The
highest sex ratios are seen in countries with a combination of preference
for sons, easy access to sex selective technology, and a low fertility
rate, as births of girls must be prevented to allow for the desired number
of sons within the family size.7 In the era of the one child policy the
fact that the problem of excess males in China seems to outstrip that of
all other countries is perhaps no surprise.6 8
Some of the evidence for this sex imbalance in China has been challenged,
because accurate population based figures have been difficult to obtain.9
10 Births classified as “illegal,” violating the one child policy, may be
concealed to avoid penalties.11 12 Under-reporting of births of girls may
be more common in this context, leading to spuriously high sex ratios at
birth.13 14 However, if girls are not reported at birth, they are likely to
filter into the statistics later, as registration is necessary for
immunisation or to start school.15 Therefore, examining the sex ratio
across different age bands provides a more accurate picture.
The objectives of this study were to elucidate current trends and
geographical patterns in the sex ratio at birth and in the population under
the age of 20 in China and to explore the role played by sex selective
abortion and the one child policy in the sex imbalance.
Methods
We analysed data from the intercensus survey of 2005, which was carried out
on a representative 1% of the total population in November 2005 and is the
most recent national population survey. It used the same basic
organisation, procedures, and questionnaire as the fifth census of 2000,
but the mode of implementation took into account acknowledged deficiencies
of the 2000 census, which led to under-numeration of the population by an
estimated 1.8%, mostly in the youngest age groups, resulting in possible
inaccuracies in the sex ratio.16 Specific measures were therefore
incorporated into this survey to solve problems of under-numeration, and
quality control methods were used to minimise sampling bias. These are
described in detail elsewhere.16 The survey covered all of China’s 2861
counties, using a three stage cluster sampling method at township, village,
and enumeration district level, with probability proportionate to estimated
size, and is hence broadly representative of the total population. The
minimal sampling unit was the enumeration district, which consisted of the
village committee in rural areas and the neighbourhood committee in urban
areas. The survey was carried out in households by staff specifically
trained in census techniques. Only data for the under 20 age group are
reported here.
Analysis—The major outcome variable is the sex ratio, defined as males per
100 females. We derived 95% confidence intervals for the sex ratios by
using the 95% confidence interval for the proportion of female births (pf)
with a variance of pf(1-pf). We calculated the excess of males for all age
groups by using an average of the mean sex ratios from 13 countries that
have normal secondary sex ratios and little or no sex preference.17 These
were 105 for the 1-9 age group and 104 for the 10-19 age group.
Results
The survey counted 4 764 512 people under the age of 20: 1 073 229 (22%)
urban residents, 813 386 (17%) town residents, and 2 877 897 (60%) rural
inhabitants. In the 12 months before the study 161 109 births were
reported: 23% in urban areas, 17% in towns, and 60% in rural areas. First
order births accounted for 63% of the total, second order for 32%, third
order for 4.3%, and fourth or higher order for 1%.
Table 1 shows the sex ratio by age group and type of residency. Sex ratios
were consistently higher than normal across residency type and all age
groups except for urban 15-19 year olds. Sex ratios peaked in the 1-4 age
group; the highest was 126 (95% confidence interval 125 to 126) in rural
areas. Table 2 shows the sex ratio by age group for all provinces. Only two
provinces, Tibet and Xinjiang, had sex ratios within normal limits across
the age range. Two provinces, Jiangxi and Henan, had ratios of over 140 in
the 1-4 age group; four provinces—Anhui, Guangdong, Hunan, and Hainan—had
ratios of over 130; and seven provinces had ratios between 120 and 129. The
provinces with the highest sex ratios are clustered together in the
central-southern region (fig 1). Notably, sex ratios were high into the
teenage groups in Hainan and Guangxi. The excess of males increased from
5.1% (n=142 634) in the cohort born between 1986 and 1995 to 9.4% (n=184
970) in the cohort born between 1996 and 2005 across the whole country. A
marked rise occurred in the percentage of excess males between the two
cohorts in all provinces except Xinjiang.
The total sex ratio at birth for the 12 months to October 2005 was 120 (119
to 121) for the whole sample (table 3), with a gradient between urban (115,
113 to 117), town (120, 118 to 122), and rural (123, 121 to 124) areas.
This equates to 11 320 excess boys born for the year for the whole sample.
The total sex ratio at birth was over 130 in three provinces (Shaanxi,
Anhui, and Jiangxi) and over 120 in 14 provinces. These overall figures
conceal dramatic differences in sex ratio at birth by birth order. The sex
ratio at birth for first order births was slightly high in cities and towns
but was within normal limits in rural areas. However, the ratio rose very
steeply for second and higher order births in cities 138 (132 to 144),
towns 137 (131 to 143), and rural areas 146 (143 to 149), although the
numbers of second order births in cities were low. These rises were
consistent across all provinces, except Tibet, with very high figures for
second births in Anhui (190, 176 to 205) and Jiangsu (192, 174 to 212). For
third births, the sex ratio rose to over 200 in four provinces, although
third births accounted for only 4.3% of the total.
Discussion
The findings paint a discouraging picture of very high and increasing sex
ratios in the reproductive age group in China for the next two decades. The
sex ratio increased steadily from 108 (108 to 109) in the cohort born
between 1985 and 1989 to 124 (123 to 124) in the 2000 to 2004 cohort.
However, the ratio then declined to 119 (119 to 120) for the 2005 cohort,
perhaps indicating the beginning of a reduction in sex ratios for the
future. Sex ratios were outside the normal range for almost all age groups
in almost all provinces. The sex ratios rose dramatically between first and
second order births, with very high sex ratios for the very few higher
order births. Tibet and Xinjiang were the notable exceptions. The highest
ratios were seen in the centre and south of the country, in the highly
populous provinces of Henan, Jiangxi, Anhui, Guangdong, and Hainan.
Extrapolating from this 1% sample to the whole country, we estimate that an
excess of 1 132 000 boys were born in the 12 months to October 2005 and
that an excess of 32 706 400 males under the age of 20 existed in the whole
of China at that time, 18 497 000 of them under the age of 10.
This is the most recent nationwide demographic survey in China, a country
undergoing rapid socioeconomic change, where timely data are of particular
importance. The survey used specific measures to attempt to ensure coverage
of the target group, in order to more accurately estimate the sex ratio.16
A very large survey aiming to represent 1% of the total population
obviously has some limitations. Complete coverage of households and
inhabitants is clearly impossible on such a large scale. Furthermore,
extrapolation to the whole population from a 1% sample should be done with
caution. The small sample size at provincial level in some age bands and
for second and higher order births leads to wide confidence intervals,
illustrating the uncertainty around these figures. However, the overall
credibility of the data is increased by the high sex ratios in older age
groups, for which concealment and under-reporting of girls would be
difficult, and by the number of births counted for the 12 months to October
2005 (161 109), which matches the estimate of 16 million births a year from
other sources.18 The findings increase our understanding of the roles of
sex selective abortion and the influence of the one child policy in the sex
imbalance in China and have clear policy implications.
Role of sex selective abortion
The precise role of sex selective abortion in the sex imbalance has been
unclear, not least because the practice is illegal in China and obtaining
reliable figures is therefore difficult. Some small rural studies have made
estimates for proportions of sex selective abortions from hospital based
and community birth records.19 20 21 Two concluded that sex selective
abortion was the major cause of the sex imbalance; however, local
circumstances vary hugely in China, so wider inferences need to be made
with caution. The findings of this survey help to elucidate the role of sex
selective abortion in the high sex ratio at the national level.
Firstly, if under-registration of girls, rather than sex selective
abortion, accounted for most of the excess births of boys, then sex ratios
would fall from birth through early childhood, as girls are required to be
registered for immunisation and school entry.15 Our finding that the sex
ratios for the 1-4 year old cohort are higher than those at birth and in
infancy tends to refute this hypothesis, suggesting that the rise in the
1-4 age group is a cohort effect—that is, it reflects the higher sex ratio
at birth in this cohort. To further investigate the role of
under-registration, comparison can be made between each cohort specific sex
ratio and the corresponding sex ratio at birth from previous census data.22
23 This shows that with only one exception, the 15-19 year old cohort born
between 1985 and 1989, the sex ratio at birth was higher or very close to
the sex ratio of the corresponding birth cohort in the 2005 survey: the age
1-4 cohort had a sex ratio of 124 and a sex ratio at birth of 120, the 5-9
cohort had a sex ratio of 119 and a sex ratio at birth of 118, the
corresponding ratios for the 10-14 cohort were 114 and 112, and those for
the 15-19 cohort were 108 and 111. This lends support to the assertion that
under-registration of girls is not a major contributor to high sex ratios
at birth. Infanticide is of course another possible explanation for girls
missing at birth, but this is widely acknowledged to be very rare now.24 25
26 27
Secondly, the dramatic increase in sex ratio with second births that our
data document, shows that couples are selecting to ensure a boy, the so
called “at least one son practice.”15 In urban areas where few couples are
allowed a second child, the high sex ratio for first order births (110, 95%
confidence interval 107 to 113) suggests some sex selection occurring with
the only child. This pattern of dramatic increases in sex ratios for second
children is not unique to China. In both South Korea and parts of India,
where overall sex ratios are high, the sex ratio increases dramatically for
second and higher order births, which has been attributed to sex selective
abortion, as couples try to ensure the birth of male offspring while
limiting their family size.7 28
Thirdly, the steady rise in sex ratios across the birth cohorts since 1986
mirrors the increasing availability of ultrasonography over that period.
The first ultrasound machines were used in the early 1980s; they reached
county hospitals by the late 1980s and then rural townships by the
mid-1990s.21 29 Since then, ultrasonography has been very cheap and
available even to the rural poor. Termination of pregnancy is also very
available, in line with the one child policy.26 Although sex selective
abortion is illegal, proving that an abortion has been carried out on sex
selective as opposed to family planning grounds is often difficult when
abortion itself is so readily available.21
Role of one child policy
The relation between the sex ratio and the one child policy is a complex
one. This study covers births taking place after the policy was instigated,
so the increase in sex ratio that we document across age cohorts born in
the past 20 years cannot be blamed on the policy in itself. However, the
policy is implemented differently across the country (fig 2), and our data
do suggest that the sex ratio is related to the way in which the policy is
implemented.15 Whereas in most cities only one child is allowed, three main
variants of the policy exist in rural areas. Type 1 provinces are most
restrictive—around 40% of couples are allowed a second child but generally
only if the first is a girl. In type 2 provinces everyone is allowed a
second child if the first is a girl or if parents with one child experience
“hardship,” the definition of which is open to interpretation by local
officials. Type 3 provinces are most permissive, allowing couples a second
child and sometimes a third, irrespective of sex. Our data show that the
type 2 variant, which allows couples a second child after a girl, results
in the highest sex ratios for second order births and the overall highest
sex ratios, as seen in Henan, Anhui, Jiangxi, Hunan, Guangdong, and Hainan.
These are largely more traditional, predominantly agricultural provinces,
where bearing sons is still seen as necessary for long term security.21 29
Medium sex ratios were most common in the strict type 1 provinces. However,
these provinces are also wealthier, levels of education are higher,
especially among women, traditional values of preference for sons are
changing, and more people have pensions making them less dependent on sons
to provide security in old age.30 A study in 2001 showed that more than 50%
of women of reproductive age in such provinces express no preference for a
son.31 The lowest (most normal) ratios are seen in the type 3, most
permissive, provinces, such as Tibet, Xinjiang, and Ningxia. However, these
provinces are also sparsely populated and poor, inhabited partly by ethnic
groups who are generally less inclined to prefer sons and less accepting of
abortion.29
This analysis is inevitably simplistic, given intra-provincial diversity,
but the findings do point to the tendency for the type 2 variant of the
policy to result in high sex ratios. The policy implications are clear:
changing the regulations in force in type 2 provinces, which permit most
couples a second child after a female birth, could help to reduce the sex
ratio. Indeed, some commentators have gone further: now that the fertility
rate is below replacement, some have recommended that all couples should be
allowed two children irrespective of sex,30 31 32 and relaxation of the
policy is expected over the next decade.
Although some imaginative and extreme solutions have been suggested,33 34
nothing can be done now to prevent this imminent generation of excess men.
The government is very aware of the problem and has openly expressed
concerns about the consequences of large numbers of excess men for societal
stability and security.22 As early as 2000 the government launched a range
of policies to specifically counter the sex imbalance, the “care for girls”
campaign. This includes changes in laws in areas such as inheritance by
females, as well as an educational campaign to promote gender equality.
These measures have had some success, with reports of lower sex ratios at
birth in targeted localities.22 This shows that change is occurring. In
addition, the finding that the sex ratio at birth did not increase between
2000 and 2005, and that the ratio for the first (and usually only) birth in
many urban areas is within normal limits, means that the sex ratio may fall
in the foreseeable future.
What is already known on this topic
• The reported sex ratio (males per 100 females) in China is high, but
accurate population based figures for actual sex ratios have been
notoriously difficult to obtain
• The role of sex selective abortion and the influence of the one child
policy on the sex imbalance have been unclear
What this study adds
• China will see very high and steadily worsening sex ratios in the
reproductive age group for the next two decades
• Sex selective abortion accounts for almost all the excess males
• One particular variant of the one child policy leads to the highest sex
ratios
Notes
Contributors: All the authors participated in the analysis and in preparing
the tables and saw and approved the final version of the paper. ZWX is the
guarantor.
Funding: This study was funded through a China-UK excellence fellowship for
TH from the Department of Innovation, Universities and Skills.
Competing interests: None declared.
Ethical approval: Not needed.
Notes
Cite this as: BMJ 2009;338:b1211
References
1. James WH. The human sex ratio. Part 1: a review of the literature. Human
Biology 1987;59:721-5.
2.Teitelbaum M. Factors affecting the sex ratio in large populations. J Bio
Sci 1970:2:61-71.
3.Arnold F. The effect of son preference on fertility and family planning:
empirical evidence. Popul Bull UN 1987;23:44-55.
4.Klasen S, Wink C. A turning point in gender bias in mortality? An update
on the number of missing women. Popul Dev Rev 2002;28:285-312.
5.Sen A. Missing women revisited. BMJ 2003;327:1297-8. [PubMed]
6.Hesketh T, Zhu WX. Abnormal sex ratios in human populations: causes and
consequences. Proc Natl Acad Sci USA 2006;103:13271-5. [PubMed]
7.Park CB, Cho NH. Consequences of son preference in a low fertility
society: imbalance of the sex ratio at birth in Korea. Popul Dev Rev
1995;21:59-84.
8.Gu B, Roy K. Sex ratio at birth in China, with reference to other areas
in East Asia: what we know. Asia Pac Popul J 1995;10:17-42. [PubMed]
9.Short SE, Zhai FY. Looking locally at China’s one-child policy. Stud Fam
Plan 1998;29,4:373-87.
10.Merli MG, Raftery AE. Are births underreported in rural china?
Manipulation of statistical records in response to China’s population
policies. Demography 2000;37:109-26. [PubMed]
11.Banister J. Shortage of girls in China today. J Popul Res 2004;21:19-45.
12.Johansson S, Nygren O. The missing girls of China: a new demographic
account. Popul Dev Rev 1991;17:35-51.
13.Zeng Y, Tu P, Gu B, Xu L, Li B, Li Y. Causes and implications of the
recent increase in the reported sex ratio at birth in China. Popul Dev Rev
1993;19:283-302.
14.Coale A. Excess female mortality and the balance of the sexes in the
population: an estimate of the number of missing females. Popul Dev Rev
1991;17:518.
15.Attane I. China’s family planning policy: an overview of its past and
future. Stud Fam Plan 2002;33:103-13.
16.Zhang W, Li X, Cui H. China’s intercensus survey in 2005 Beijing: China
Population Publishing House, 2007.
17.Ulizzi L, Astolfi P, Zonta LA. Sex ratio at reproductive age: changes
over the last century in the Italian population. Hum Biol 2001;73:121-8.
[PubMed]
18.China-Profile. Facts, figures, and analyses. www.china-profile.com.
19.Wu Z, Viisainen K, Hemminki E. Determinants of high sex ratio among
newborns: a cohort study from rural Anhui Province. Reprod Health Matters
2006;14:172-80. [PubMed]
20.Lofstedt P, Luo SS, Johansson A. Abortion patterns and reported sex
ratio in rural Yunnan, China. Reprod Health Matters 2004;12:86-95. [PubMed]
21.Chu JH. Prenatal sex determination and sex-selective abortion in rural
central China. Popul Dev Rev 2001;27:259-81.
22.Li S. Imbalanced sex ratio at birth and comprehensive intervention in
China. Presentation at 4th Asia Pacific Conference on Reproductive and
Sexual Health and Rights, Hyderabad, 29-31 October 2007. Available at
www.unfpa.org/gender/docs/studies/china.pdf.
23.China Population Information and Research Centre. Basic population data
of China: 1949-2000. www.cpirc.org.cn.
24.Hesketh T, Zhu WX. The one child family policy: the good, the bad and
the ugly. BMJ 1997;314:1685-7. [PubMed]
25.Wu ZC, Viisainen K, Wang Y, Hemminki E. Perinatal mortality in rural
China: retrospective cohort study. BMJ 2003;327:1319-22. [PubMed]
26.Hemminki E, Wu ZC, Cao GY. Illegal births and legal abortions—the case
of China. Reprod Health Matters 2005;2:5.
27.Li S, Zhu C, Feldman M. Gender differences in child survival in
contemporary rural China: a county study. J Biosoc Sci 2004;36:83-109.
[PubMed]
28.Jha P, Kumar R, Vasa P, Dhingra N. Thirichelvam D, Moineddan R. Low male
to female sex ratio of children born in India: national survey of 1.1
million households. Lancet 2006:367:211-8.
29.Li R. An analysis of the sex ratio at birth in impoverished areas in
China. Chin J Popul Sci 1998;10:65-73. [PubMed]
30.Winkler EA. Chinese reproductive policy at the turn of the millennium:
dynamic stability. Popul Dev Rev 2002;28:379-418.
31.Qu JD, Hesketh T. Family size, sex ratio and fertility preferences in
the era of the one child family policy: results from the national family
planning and reproductive health survey. BMJ 2006;333:371-3. [PubMed]
32.Zeng Y. Options for fertility policy transition in China. Popul Dev Rev
2007;33:215-46.
33.Tuljapurkar S, Li N, Feldman MW. High sex ratios in China’s future.
Science 1995;267:874-6. [PubMed]
34.Hudson V, Den Boer AM. A surplus of men, a deficit of peace: security
and sex ratios in Asia’s largest states. Int Secur 2002;4:5-38.